Canon 2000 Service Manual Download Page 338

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A–32

7.3.3 Echo countermeasures

The following describes the main countermeasures against echo that are

adopted on Canon facsimiles.

(1) Countermeasure on Receiver

Add a tonal signal (1080 Hz, 0.5 sec) before the CED tone (selected by the

SSSW).

By adding a tone other than 2100±21 Hz before CED, disabling of the

echo suppressor can be prevented.

A tone of 1080 Hz is added on Canon facsimiles.

Fig. A-33 Echo Countermeasure on Receiver

CED

Preamble

NSF

CSI

DIS

Tonal signal
(1080 Hz, 0.5 sec)

Long distance
transmission line

Summary of Contents for 2000

Page 2: ...d company names described in this manual are the registered trademarks of the individual companies Copyright This manual is copyrighted with all rights reserved Under the copyright laws this manual may not be copied reproduced or translated into another language in whole or in part without the written consent of Canon Inc Copyright 2000 by Canon Inc CANON INC Office Imaging Products Technical Supp...

Page 3: ...eir studies with Chapters 1 and 2 Those already servicing facsimiles or those who already understand facsimiles to a certain extent may refer to chapters that meet their particular requirements This manual is made up of the following chapters Chapter 1 BASIC OF TELEPHONE Chapter 2 GENERAL DESCRIPTION OF A FACSIMILE Chapter 3 READING SECTION Chapter 4 RECORDING SECTION Chapter 5 G3 FACSIMILE COMMUN...

Page 4: ...LEPHONES 1 11 Dial Telephones 1 11 Pushbutton Telephones 1 11 Digital Telephones 1 12 CIRCUIT DIAGRAM IN THE TELEPHONE 1 13 Dial Telephones 1 13 Pushbutton Telephone 1 14 INTRODUCTION TO THE TELEPHONE NETWORK 1 15 Parts of a Telephone Network 1 15 Basic Structure of a Telephone Network System 1 19 Nationwide Telephone Network In case of Japan 1 20 TELEPHONE EXCHANGES 1 25 Types of Exchanges 1 25 T...

Page 5: ...ING METHODS 3 3 Sheet Reading Method 3 3 Book Reading Method 3 4 ADF Type 3 4 CONTACT SENSOR 3 10 Structure of Contact Sensor 3 10 Features of Contact Sensor 3 10 IMAGE DATA PROCESSOR 3 14 Various Image Data Processing 3 14 CHAPTER 4 RECORDING SECTION INTRODUCTION 4 2 IMAGE DATA PROCESSING SECTION 4 3 Image Area Separation Processing Smoothing Processing and Selector 4 4 Reproduction Ratio Process...

Page 6: ...Coding Necessary 5 8 MH Coding Scheme One dimensional Coding Scheme 5 10 MR Coding Scheme Two dimensional Coding Scheme 5 17 MMR Coding Scheme 5 28 JBIG Image Compression Encoding Scheme 5 29 MODULATION METHOD 5 45 Modulation and Demodulation 5 45 Shift and Modulation Methods 5 46 Modulation Methods up to 9600 bps 5 47 High speed MODEMs above 14400 bps 5 55 V 17 V 33 MODEM Technology 5 55 V 34 MOD...

Page 7: ...gnal Monitor 6 10 Dial Control 6 11 2 wire 4 wire Conversion 6 12 Protective Circuits 6 12 Telephone Connection Control 6 14 Relay Operations 6 17 OPCNT BOARD 6 18 Detection of Button Input 6 18 LED Lighting Control 6 21 Display Indication Control 6 21 FLOW OF IMAGE SIGNALS 6 22 Transmission 6 22 Reception 6 23 POWER SUPPLY UNIT 6 24 Switching Regulator 6 24 Configuration of Power Supply Unit on a...

Page 8: ... LINE BAND SIGNAL SPECTRUM A 19 S N A 20 POLARITY INVERSION ON EXCHANGE A 21 FACTORS WHICH CAUSE DETERIORATION IN QUALITY OF FACSIMILE TRANSMISSION A 22 Usual Factors A 22 Unusual Factors A 27 Echo A 28 RATIO dB dBm dBV A 35 BINARY SIGNALS TABLE A 39 MAKER CODES TABLE A 42 STANDARD DOCUMENT SIZES A 44 G3 FACSIMILE TRANSMISSION CONTROL PROCEDURES A 45 GLOSSARY A 67 INDEX I 1 ...

Page 9: ...2 4 Hook Button 1 8 2 5 Dial 1 9 2 6 Bell Speaker 1 10 3 TYPES OF TELEPHONES 1 11 3 1 Dial Telephones 1 11 3 2 Pushbutton Telephones 1 11 3 3 Digital Telephones 1 12 4 CIRCUIT DIAGRAM IN THE TELEPHONE 1 13 4 1 Dial Telephones 1 13 4 2 Pushbutton Telephone 1 14 5 INTRODUCTION TO THE TELEPHONE NETWORK 1 15 5 1 Parts of a Telephone Network 1 15 5 2 Basic Structure of a Telephone Network System 1 19 5...

Page 10: ... even though they use it every day Let s learn the names of the parts on a telephone Fig 1 1 Parts of the Telephone What we generally refer to as the receiver was in fact the handset The receiver is the part that we hold against the ear on the handset Likewise the part that we bring near our mouth on the handset is called the transmitter Some people mistakenly refer to the handset as the receiver ...

Page 11: ...alled the outgoing call and the call that arrives is called the incoming call Fig 1 3 Telephone Call State 1 When you lift the handset the handset is off hook When you hang up the handset is on hook These days some telephones have an on hook button For example even if the handset is placed on the telephone body pressing this on hook button sets the telephone to the same state on hook as when the h...

Page 12: ...other party picks up the handset the exchange stops sending the ringing tone so that you can have a conversation 6 You have your conversation 7 You hang up When the called number is in use the calling party hears a busy tone Even if the called party hangs up while the caller is listening the calling party will still hear the busy tone So the calling party needs to dial again 1 4 Voice Frequencies ...

Page 13: ...and a hook button Of these parts the parts that play the most important roles are the transmit ter and the receiver The transmitter converts human voice to electrical sig nals and the receiver converts the electrical signals from the other party to voice Here let s learn about the mechanism of these parts and the roles that they perform Fig 1 5 Handset Receiver Transmitter ...

Page 14: ...ance decreases When the powder is released its contact resistance increases So direct current varies corresponding to the change of pressure voice This is called voice current Recently a microphone is applied to the transmitter of the telephone Fig 1 6 Transmitter and Voice Current Carbon powder Fixed electrode Diaphragm Air vibration Contact resistance Voice current ...

Page 15: ...rating diaphragm according to the current strength Fig 1 7 Receiver 2 3 Voice Circuit When the transmitter and receiver are connected as shown in the Fig 1 8 to make a voice circuit voice can be transmitted in both directions along the two wires Fig 1 8 Two way Circuit Two Wires Armature Permanent magnet Diaphragm R R T T Calling party Exchange Called party T Transmitter R Receiver ...

Page 16: ...e detects this direct current to recog nize that the handset has been picked up Fig 1 10 DC Loop Picking up a handset is called making a DC loop A DC loop lets the exchange know that 1 The calling party the party making the call is ready to call someone 2 The called party answered The party receiving the call 3 The handset is on hook Hook button Hook button T Transmitter R Receiver HS Hook switch ...

Page 17: ...the dial returns to its start position after the number 4 is dialed the DC loop is cut four times This is called the dial pulse Dialing using this dial pulse is called pulse dial due to the fact that num bers are dialed by this pulse Fig 1 11 Dial Pulse The exchange selects and calls up the other party by counting the number of dial pulses Dials return to their start position at either of two spee...

Page 18: ... pulses is the dialed number N 1 The number of dial pulses is the dialed number N 1 2 6 Bell Speaker The calling identification CI signal from the exchange for notifying that you have an incoming call is converted to the ring tone and is output Recently a speaker or buzzer is used instead of the bell Dialed number 1 2 3 4 5 6 7 8 9 0 Number of dial pulses 2 3 4 5 6 7 8 9 10 1 Dialed number 1 2 3 4...

Page 19: ...g signals Pushbutton telephones have 12 buttons and have an oscillator inside to generate seven different frequencies For example if you push button 1 two frequency currents 697 Hz and 1209 Hz are sent simultaneously This is called DTMF Dual Tone Multi Frequency and dialing using this DTMF is called tone dial due to the fact that numbers are dialed by this tone Dialing is also referred to as PB Pu...

Page 20: ...utputs dial pulses even though the telephone looks like a pushbutton telephone 3 3 Digital Telephones Though digital telephones also have 12 buttons just like a pushbutton tele phone the dialing signals are output not as a tone frequency but as a code comprising a combination of digital 0s and 1s Also the signals for ringing the bell on the other party s telephone are sent as a code comprising a c...

Page 21: ...it is closed and short circuited by the switch HS2 when the handset is picked up Ringing of the bell by dial pulses is thus prevented Dial telephones are also provided with a dial shunt contact DS to prevent noise caused by the entry of dial pulses on the receiver The DS closes when you start dialing and opens when the dial has finished returning to its start position Fig 1 14 Circuit of Dial Tele...

Page 22: ...ephone Basically the only difference between the circuit of a pushbutton tele phone and the circuit of a dial telephone is that the dialing signal generator differs Fig 1 15 Basic Circuit of Pushbutton Telephone R T HS Bell T Transmitter R Receiver HS Hook switch 12 pushbuttons and DTMF generation circuit ...

Page 23: ...ers In this section let s learn about the mechanism of a telephone network 5 1 Parts of a Telephone Network To communicate over a telephone line you need two telephones a tele phone line and an exchange system The telephone is sometimes called a terminal because it is at each end of the telephone line Fig 1 16 Parts of a Telephone Network Telephone line Exchange system Telephone Terminal Telephone...

Page 24: ...er of lines needed to connect telephone is given by n n 1 2 For example you need about 500 000 lines for 1 000 telephones Clearly it is impossible to connect many telephones in a mesh network So you can see that a telephone exchange is quite necessary An exchange connects a line to a telephone when it receives a calling request In this system the number of lines can be equal to the number of telep...

Page 25: ...6 ït çi BASIC OF TELEPHONE So far we have the mesh network and the star network These are the basic types of network systems If we combine both networks into one system we have a hybrid network Fig 1 19 Hybrid Network ...

Page 26: ...tical fiber cable microwaves communications satellites and submarine cable The places where the exchange system is located is called the telephone center or the exchange center Fig 1 20 Telephone Network Organization Telephone Transit exchange Subscriber exchange Telephone Transit exchange Subscriber exchange Microwave radio relay system Satellite communication system O p t i c a l f i b e r c a b...

Page 27: ...called a subscriber line Fig 1 21 Subscriber Line and Transit Trunk As the number of telephone centers increases it becomes more economic to set up an exchange for terminating only the transit trunks and connect ing this exchange in the center in shape of a star rather than connecting telephone centers to others in the shape of an interlinked network by directly connected transit trunks This kind ...

Page 28: ...calls to a wider area Fig 1 23 Center Grade 5 3 Nationwide Telephone Network In case of Japan The nationwide network in Japan can be divided into subscriber areas matched with administrative districts A subscriber area has more than one subscriber exchange to connect all the telephones in the area A call within the area is called a local call and can be made by dialing an exchange number and the s...

Page 29: ...twork for long distance calls is toll network And the line and the exchange for the long distance call are called the toll line and the toll exchange A toll exchange is classified into three ranks toll centers district centers and regional centers Fig 1 26 Structure of Telephone Network Regional center RC RCs have been established in Sapporo Sendai Tokyo Nagoya Kanazawa Osaka Hiroshima and Fukuoka...

Page 30: ...riber area has one end office which connects all the telephones in the area In this case the subscriber area is called a single office area Fig 1 27 Single Office Area As the number of telephones increase there will also be an increase in the number of end offices called branches These branch offices are connected in a mesh network In this case the subscriber area is called a multiple office area ...

Page 31: ...big cities have a transit exchange a local tandem exchange office in a star network Generally a hybrid network is formed when many calls con centrate on certain lines Fig 1 29 Hybrid Network Subscriber area We are multiple offices Transit exchange ...

Page 32: ...s the normal transit trunk which connects upper and lower centers in the nationwide hierarchy The other is the traversal trunk which ignores this hierarchy and connects two centers to handle a great deal of calls For this reason there are actually many con nection routes and the quality of a conversation is affected by which route is taken to connect a call Fig 1 31 Actual Connection Route End off...

Page 33: ... type This mechanically proceeds with operation by dial pulses for each dialed digit This has many switch contacts and provides a mechanical exchange So normal transmission may be disturbed by a lot of noise This is not suitable for facsimile use As only dial speed 10PPS telephones can be connected this is already an outmoded type of exchange 2 Crossbar type C type This makes connection only after...

Page 34: ...nge works Fig 1 33 How an Exchange Works Operation on calling telephone Operation on exchange Operation on called telephone The exchange gets ready The exchange is ready to receive a number After receiving the signal the exchange finds the called number The exchange connects the line Unless the called number is busy Conversation The exchange stops ring tone ring back tone and connects the line The...

Page 35: ...hat the exchange is ready and you may send the dial ing signals 2 Ring Back Tone This tone indicates to the caller that the other party is being called up 3 Busy Tone This tone indicates to the caller that the other party is busy 4 Calling Identification CI This signal notifies the called party that there was a call from a caller This signal rings the bell on the called party s telephone 5 Re orde...

Page 36: ...1 28 Notes ...

Page 37: ...Telephone Lines 2 3 1 5 Types of ITU T Recommendations 2 4 1 6 How Images are Transmitted 2 8 2 STRUCTURE OF A FACSIMILE 2 13 2 1 Reading Section 2 15 2 2 Recording Section 2 18 2 3 MODEM 2 21 2 4 NCU board Network Control Unit board 2 22 2 5 System Control Section 2 22 3 THE FUTURE OF FACSIMILES 2 23 3 1 Color Facsimiles 2 23 3 2 LAN networked Facsimiles 2 23 3 3 Internet Facsimiles 2 24 ...

Page 38: ... If facsimiles were designed to conform to individual manufacturers standards we would not be able to transmit or receive documents between facsimiles made by dif ferent manufacturers It is naturally very advantageous for today s mod ern information society that facsimile communications be possible via telephone lines anywhere there is a telephone using any type of facsimile This is why establishe...

Page 39: ...arious kinds of telephone lines analog lines digital lines and Facsimile communication network services The telephone line that we use most of the time is an analog line called a PSTN Public Switched Telephone Network which has been designed for transmitting speech The information that a PSTN is capable of transmit ting are analog signals that are obtained by converting changes in current or volta...

Page 40: ...he document is stored to ensure efficient use of the line For this reason you are charged by the number of document sheets that you transmit regardless of the transmission time 1 5 Types of ITU T Recommendations This section describes the main details of recommendations relating to G3 and G4 facsimile 1 5 1 G3 facsimile related recommendations T 0 Classification of facsimile terminals for document...

Page 41: ... Procedures for starting sessions of data transmission over the public switched telephone network Description of signals to be switched between DCE Data Communi cations Equipment when establishment of a data transmission session is required over the public switched telephone network V 17 A 2 wire modem for facsimile applications with rates up to 14400 bit s TC7200 bps TC9600 bps 12000 bps and 1440...

Page 42: ... and protocols for terminals for telematic ser vices in ISDN ISDN B channel circuit switched mode ISDN B channel packet switched mode T 411 Information technology Open Document Architecture ODA and interchange format Introduction and general principles T 412 Information technology Open Document Architecture ODA and interchange format Document structures T 414 Information technology Open Document A...

Page 43: ...ion profile for the interchange of Group 4 facsimile documents Clarification of formats to be applied to group 4 facsimile document interchange T 521 Communication application profile BT0 for document bulk transfer based on the session service T 563 Terminal characteristics for Group 4 facsimile apparatus Stipulation of general characteristics of group 4 facsimile terminals ...

Page 44: ...eives and prints out the transmitted image The figures below illustrate how images are sent Fig 2 2 How Images Are Transmitted 1 Image 2 Division into pixels 3 Conversion into electrical signals 4 Modulation 6 Demodulation 7 Reassembly of pixels 8 Reproduction of image Transmission Reception 5 Transmission reception White pixel Black pixel Minus signal Plus signal ...

Page 45: ...ILE 1 Image This is the original image before it is transmit Fig 2 3 Image 2 Division into pixels The image is divided into either white or black pixels Fig 2 4 Division of Image into pixels a b c d e f g h 1 2 3 4 5 6 7 8 a b c d e f g h 1 2 3 4 5 6 7 8 ...

Page 46: ...evel signals Fig 2 5 Conversion into Electrical Signals 4 Modulation The picture signals are modulated This figure shows an example of fre quency modulation Fig 2 6 Modulation High level signal Low level signal a b c d e f g h 1 2 3 4 5 6 7 8 a b c d e f g h 1 2 3 4 5 6 7 8 High level signal Low level signal High frequency Low frequency 1 2 3 4 5 6 7 8 a b c d e f g h ...

Page 47: ...e transmitted in the order of lines a b through h Fig 2 7 Transmission Reception 6 Demodulation Image signals a through h are sequentially demodulated into the electrical signals that represent black and white pixels Fig 2 8 Demodulation a b c d e f g h Reception Transmission FAX FAX d e f g h a b c ...

Page 48: ...y reassembled Fig 2 9 Reassembly of pixels 8 Reproduction of image The black and white image information is printed on recording paper according to the electrical signals to reproduce a copy of the original pic ture Fig 2 10 Reproduction of Image a b c d e f g h 1 2 3 4 5 6 7 8 a b c d e f g h 1 2 3 4 5 6 7 8 ...

Page 49: ...ld say that a facsimile is structured by integrating a scanner reading section and printer recording section in a telephone and providing it with a communications function modem for handling data exchange transactions with the other party via a telephone line NCU board Fig 2 11 Structure of a Facsimile Fig 2 12 is a block diagram of these facsimile s electric systems ...

Page 50: ...other data such as telephone num bers The main functions of the system control section include scanning control for accepting image data from the image sensor drive control for driving the motors and other moving parts recording control for operating the recording section image data control for transmitting image data to the modem and receiving image data and modem control for operating the modem ...

Page 51: ...single photosensor and a rotating cylinder that enables two dimensional movement around the sensor The document is wound around the cylinder and the photosensor is moved in the direction of the cylinder shaft while the cylinder is rotated The direction that the document rotates is the horizontal scanning and the direction that the photosensor moves is the vertical scanning This scanning method was...

Page 52: ...photosensor itself CCD image sensors and contact sensors are two types of photosensor used in flat bed scanning 1 CCD image sensor system Though the CCD image sensor itself is small the optical path up to the document must be lengthened which makes CCD image sensors unsuit able for downsizing of reading sections Nevertheless this system has the advantage over a contact sensor as its reading speed ...

Page 53: ...that they can be downsized This system is used on small medium and large size machines accompanying progresses in image processing technology Fig 2 15 Flat bed Scanning contact sensor system Contact sensor The phototransistor in the contact sensor reads one horizontal scanning line at a time Document Document reading direction Document feed direction LED array photoemitter Phototransistor array ph...

Page 54: ...its surface Heat is generated by a thermal element ther mal head that is held in contact against the surface of the color forming layer This recording method has a drawback in that it is not suitable to long peri ods of storage as heat sensitive paper fades with time However it has the advantages that facsimiles can be made compact due to its simple structure and is maintenance free For these reas...

Page 55: ...he advan tage that recording paper that has been received can be written and stamped on It is also ideal for storage as it is not curled up and does not discolor In spite of the fact that it uses plain paper to record on its struc ture is relatively simple which allows facsimiles to be made compact For this reason it is being used more and more in household facsimiles Fig 2 17 Ink Jet Recording Me...

Page 56: ... recording method has the same advantages as the ink jet recording method as it uses plain paper as the recording paper It also has an extra feature in that it records at high speed However as its structure is rela tively elaborate and expensive it is widely used in medium and high class facsimiles Fig 2 18 Electrophotographic System 4 Transfer Photosensitive drum Transfer charging roller static c...

Page 57: ...tored to their original state A device that modulates signals is called a modulator and a device that demodulates signals is called a demodulator A device that can perform both modula tion and demodulation is called a MODEM MOdulator and DEModula tor As the frequency bandwidth of a telephone line is between 300 to 3 400 Hz the modulation methods indicated below recommended by ITU T are used as the...

Page 58: ... telephone line to perform control of connection to the telephone or the modem Fig 2 20 NCU board Location 2 5 System Control Section The role of this control section includes the control of all facsimile devices mainly the CPU program ROM and memory data processing and saving of data Generally the system control section corresponds to the electrical circuit boards called the SCNT board or IP boar...

Page 59: ... LAN networked Facsimiles LANs Local Area Networks in offices are spreading at a rapid rate As a result various trends are beginning to emerge These include the remote control of facsimile functions For example a possible application could be to call up a letter drafted on a networked personal computer then call up a facsimile networked on the same LAN let s call this facsimile a LAN FAX and then ...

Page 60: ...ully integrate e mail and facsimiles then the facsimile will come to be usable on the Internet The specifications of an Internet facsimile have been under review since 1996 by the IETF on the premise that e mail services will be incorporated Standards centering around RFC 2305 were determined in March of 1998 and these were turned into recommendation T 37 simple mode in July 1998 with the cooperat...

Page 61: ...ket as facsimiles to be connected to LANs and the Internet as facsimiles for connection to net work systems For this reason conventional knowledge of telephone lines and facsimiles will not be sufficient for handling these products Improv ing and acquiring knowledge of LAN technology Internet technology and LAN related networks will prove to be all the more important from now on ...

Page 62: ...Notes 2 26 ...

Page 63: ... 3 2 2 READING METHODS 3 3 2 1 Sheet Reading Method 3 3 2 2 Book Reading Method 3 4 2 3 ADF Type 3 4 3 CONTACT SENSOR 3 10 3 1 Structure of Contact Sensor 3 10 3 2 Features of Contact Sensor 3 10 4 IMAGE DATA PROCESSOR 3 14 4 1 Various Image Data Processing 3 14 ...

Page 64: ...ile At the reading section a document comprising two or more sheets is fed one sheet at a time to the image sensor e g contact sensor where it is read and the resulting image data undergoes image processing Fig 3 1 Reading Section Contact sensor Document feed path To image processing section ...

Page 65: ...by the forwarding roller Next the separation roller and separation guide separate the document one sheet at a time from the bottommost sheet After the document sheets are separated they are fed to the contact sensor by the feed roller After the document is read by the contact sensor it is output by the eject roller Fig 3 3 Sheet Reading Reading method Sheet reading method ADF type Flat bed type Dr...

Page 66: ...ocument comprising many sheets On the other hand however it costs more as a forwarding roller is required in the mechanism and more installation space is required Double feeding sometimes occurs due to over insertion of document sheets when the docu ment is loaded or alternatively sheets being non fed due to an insufficient amount of sheets being loaded Explanation of flat bed type operation By th...

Page 67: ...ng roller picks up the document as far as the separation roller and separation guide Fig 3 6 Document Pickup Document feed path Document pressure plate Document sensor actuator Separation guide Upper feed roller Document edge sensor actuator White mylar sheet Upper eject roller Forwarding roller Separation roller Feed roller Contact sensor Eject roller Document Document pressure plate Document sen...

Page 68: ... three friction coefficients must be satisfied µ1 µ2 µ3 Fig 3 7 Document Separation 3 Document feed operation After the document is separated the document sheets are fed to the contact sensor by the feed roller When the leading edge of the document pushes up the actuator of the document edge sensor located at the feed roller sec tion monitoring of the document length begins To prevent slack in doc...

Page 69: ...n When the trailing edge of the document has passed out of the separation roller pulling back by the spring clutch inside the separation roller stops and the separation roller enters the separation process for the second docu ment sheet When the trailing edge of the document passes the feed roller Document Document pressure plate Document sensor actuator Separation guide Upper feed roller Document...

Page 70: ...d problems caused by over insertion of the document or insufficient insertion Some types are also designed with separation rollers provided above and below in place of the separation guide and with an inversion roller to improve separation performance Fig 3 11 Document Stopper Document Document edge sensor actuator Upper eject roller Forwarding roller Separation roller Feed roller Eject roller Doc...

Page 71: ...rds output documents tend to stack poorly On the other hand however it costs less as a forward ing roller is not required and less installation space is required as the doc ument feed path is inclined Fig 3 12 Drop in Type ADF Explanation of drop in type operation The same operations as for a flat bed type ADF are performed for drop in type ADFs except that there is no document forwarding operatio...

Page 72: ...ype 1 Multi chip type Unevenness of the sensor chip is less than that of the α Si type Image quality is good as the gamma characteristics are proportional Documents can be read even if they rise off the glass surface slightly This is dependent though on the performance of the rod lens array The document need not be held down by rollers So photographs need not be pasted onto a sheet for reading The...

Page 73: ...ion is read as black So the document must be held down by a roller As the document is pressed against the glass surface there is the possi bility that documents that tend to stick such as photographs cannot be fed As the roller is held in contact with the glass surface it is difficult to clean the contact sensor ...

Page 74: ...output of that driver circuit is converted to serial data to be transmitted to the system controller Fig 3 14 Multi chip Type Reflected light Reading surface Radiated light Document feed direction Guide mylar sheet LED circuit board LED array light emitting section Contact glass Rod lens array Sensor circuit board Photo transistor array light receiving section Sensor driver1 Sensor driver2 Analog ...

Page 75: ...lass substrate has a built in driver circuit for amplifying the output of the received light and the output of that driver circuit is converted to serial data to be transmitted to the system controller Fig 3 16 α Si Type LED array Glass substrate Sensor Document feed direction Document Control circuit Sensor driver4 Analog serial output Sensor drive voltage LED Sensor driver3 Sensor driver2 Sensor...

Page 76: ... the start of document reading so that the unevenness compensation values for the output contact sensor are stored to shading memory DC generation DC generation matches the black side reference voltage of the A D conver sion circuit with that of the contact sensor AGC circuit AGC Auto Gain Control adjusts for unevenness in the reading system LED white mylar sheet and contact sensor to prevent the ...

Page 77: ... into analog signals It also generates the white side reference voltage for the A D conversion circuit ABC circuit The ABC Auto Background Control function converts the level of the skin color density in a document so that the reading density of skin color in a color background document is adjusted as white skin color This function is achieved by varying the white reference voltage of the A D conv...

Page 78: ...contact sensor are blurred or collapsed compared with the contours of the original image For this reason the edge emphasis section compensates for blurring or collapsing of the contours so that the read image is reproduced more faithfully to the original image Notch processing Notch processing is for processing notches in binary data that is processed by simple binarization By notch processing unw...

Page 79: ... Section 4 12 3 2 Feed Eject Section 4 17 3 3 Detection of Recording Paper Jams 4 19 4 PRINTING SECTION 4 24 4 1 LBP LASER Beam Printer 4 24 4 2 Printing by LASER 4 24 4 3 Flow of Printing 4 26 4 4 Video Control Section Printer Engine Control Section 4 27 4 5 LASER Scanner Section 4 32 4 6 Printing Process 4 34 4 7 Toner Cartridge 4 46 4 8 BJ Bubble Jet Printer 4 48 4 9 Printing by Bubbles 4 48 4 ...

Page 80: ...ng paper is picked up printed and output The recording section can be broadly divided into the following three sec tions Image data processing section Paper feed section Printing section This chapter describes each of the components that comprise a recording section referring to an LBP LASER Beam Printer and a BJ printer Bub ble Jet Printer that are currently the main engines for facsimiles ...

Page 81: ... image data more smoothly At the same time in the image area separation processing judgment is performed as to whether the image data is binary data or an image containing half tones such as a photo The selec tor selects whether or not the data is the original data or smoothing data based upon the judgment results by the image area separation processing The image data is then reduced as necessary ...

Page 82: ...ck white reversions that are used for judgment and the judgment criteria Number of isolated pixels The focus is applied to a certain single pixel and the total number of iso lated pixels in a given matrix centered around that pixel is calculated For example if a certain pixel is white and the adjacent four pixels are black then that pixel is said to be an isolated pixel Fig 4 2 Number of Isolated ...

Page 83: ... number of black white reversions number of arrows is 16 when the focus pixel is black Judgment criteria The image is judged to be a binary image or an image containing half tones when the following condition is satisfied Binary image When the number of isolated pixels is the stipulated number or less and the number of black white reversions is the stipulated number or less Image containing half t...

Page 84: ... is performed when image data of a standard resolution is printed on a fine resolution printer The focus is applied to a certain single pixel When smoothing is per formed on that pixel a pixel pattern enclosed by a dashed line is refer enced Fig 4 4 Smoothing 1 Whether or not the smoothing judgment pattern matches the pixel pattern enclosed by the dashed line is investigated If it matches the focu...

Page 85: ... of the smoothing data or original data based upon the result of judgment performed by the image area separation pro cessing If the document is judged to be a binary image the smoothing data is sent to the scaling processor and if the document is judged to be an image containing half tones the original data is sent Standard image Fine converted image Super fine converted image Ultra fine converted...

Page 86: ...t system For this reason image data of a resolution expressed in the millimeter unit system is converted to resolution expressed in the inch unit system held by the printer This is called mm inch conversion mm inch conversion is performed regardless of whether or not scaling types 1 to 3 described above are performed Next let s describe an instance where image data of fine resolution is printed on...

Page 87: ...n mm inch conversion Fig 4 7 mm inch Conversion When printing is actually performed density conversion of pixels hori zontal scanning direction is also performed simultaneously with mm inch conversion This example describes a case where printing is performed on a BJ printer The purpose of density conversion is to prevent smudging when ink adheres to the recording paper and to prevent the printed i...

Page 88: ...nversion 1 Such mechanisms as mm inch conversion and density conversion are per formed simultaneously on this image data Fig 4 9 mm inch Conversion and Density Conversion 2 White pixel 8 dots mm 1 2 3 4 5 6 8 9 7 Black pixel Density conversion pattern Pattern 1 Pattern 2 Pattern 3 Black pixel White pixel 3 4 5 6 8 8 dots mm 1 2 3 4 5 6 8 9 7 Pattern 1 Pattern 3 Pattern 2 360 dots inch 3 4 5 6 8 1 ...

Page 89: ...nverting areas of the image data containing lots of black pixels to white To be more precise the focus is applied to a certain single pixel and the pixels to the left right top and bottom of that pixel are investigated If all of the pixels to the left right top and bottom of that pixel are black the focus pixel is converted to white The following three patterns are available according to the numbe...

Page 90: ... The pickup method is broadly divided into two methods cassette method and ASF Auto Sheet Feeder method Even in these two pickup methods the pickup method is further categorized according to the separation method of the recording paper 3 1 1 Cassette method With this cassette method the paper cassette filled with recording paper is attached onto the body of the facsimile This method allows a relat...

Page 91: ...assette holds down the recording paper When the recording paper is picked up by the pickup roller the retention force of the claw holds down the second sheet of recording paper onwards and separates only the first sheet of recording paper Fig 4 13 Claw Separation Method A 4 Claw Claw Recording paper Pickup roller ...

Page 92: ...ied to the reverse roller via a torque limitter However as the torque of the reverse roller is smaller than the torque of the separation roller the reverse roller is pulled back to the separation roller to rotate in the clockwise direction pickup direction Fig 4 14 Reverse Roller Method 1 Operation during normal paper pickup The reverse roller is pulled back onto the recording paper and rotates in...

Page 93: ...r first sheet on the separation roller side is fed to the printing section Fig 4 16 Reverse Roller Method 3 3 Friction plate method The friction plate is held against the pickup roller and the recording paper is separated by the stopping power caused by friction The principle of operation is the same as the Chapter 3 Document Separation Operation on page 3 6 Fig 4 17 Friction Plate Method 1st shee...

Page 94: ... this method is that it allows the mechanism to be designed more compactly The same configuration is also adopted in the sub pickup meth ods of units that adopt the cassette method Claw separation and friction plate separation methods are available as the separation method used in ASF methods The principle of operation is the same as the separation method in the cassette method Fig 4 18 ASF Paper ...

Page 95: ...ording paper that arrives from the pickup section is sent to the printing section by the feed roller and is output to the recording paper out put exit by the eject roller after it has been printed Fig 4 19 Paper Feed Eject Section Feed roller Printing section Eject roller ...

Page 96: ... output in order from the last page print in order Some types of machines allow the user to select whether to output the facsimile printed side face down or face up by switching the paper delivery selector These types of output are called face down paper delivery and face up paper delivery respectively Fig 4 20 Face up Paper Delivery and Face down Paper Delivery Face up paper delivery Paper delive...

Page 97: ...ecording paper When the light that is irradiated from the light emitting section of the photo interrupter is detected by the light receiving section the sensor turns ON Alternately when light is blocked by the actuator and cannot be detected by the light receiving section the sensor turns OFF Changing of the ON OFF state of the sensor in this way is used for detecting the presence of recording pap...

Page 98: ...of the recording paper within a specified period of time after the pickup operation has started when the sensor cannot detect the trailing edge of the recording paper within a specified period of time after the sensor has detected the lead ing edge of the recording paper Fig 4 22 Pickup Jam Recording paper Pickup sensor Recording paper ...

Page 99: ...am occurs when the eject sensor cannot detect the leading edge of the recording paper within a specified period of time after the pickup sensor has detected the trailing edge of the recording paper Fig 4 23 Feed Jam Pickup sensor Eject sensor Recording paper ...

Page 100: ...detected a no recording paper state within a specified period of time after the eject sensor has detected the leading edge of the recording paper Fig 4 24 Fixing Unit Wrap around Jam Fixing roller Windup onto fixing roller Eject sensor Recording paper Recording paper Eject sensor detected no recording paper state ...

Page 101: ... This jam occurs when the eject sensor cannot detect the trailing edge of the recording paper within a specified period of time after the eject sensor has detected the leading edge of the recording paper Fig 4 25 Eject Jam Recording paper Eject sensor ...

Page 102: ...t printing speed as it is a type of page printer and prints images in single pages at a time 4 2 Printing by LASER Image data is divided into pixel dot units Each of these pixels is made to correspond to a LASER spot and images are printed by turning LASER spots ON and OFF Fig 4 26 LASER Printing 1 As the LASER beam itself only advances straight the LASER beam is reflected on a rotating scanning m...

Page 103: ...4 25 1 2 3 4 5 6 ït çi RECORDING SECTION Fig 4 27 LASER Printing 2 Scanning mirror rotating Scanning direction LASER beam ...

Page 104: ...ion The printer engine control section generates the signals LASER drive signals for turning the LASER ON and OFF based upon the video signals and sends these signals to the LASER scanner sec tion System control section Printer engine control section Printer engine section LASER scanner section Eject section Print preparations Recording paper Image data Print instruction Video signals LASER drive ...

Page 105: ...tail 4 4 Video Control Section Printer Engine Control Section At the video control section the image data that has undergone image pro cessing is converted to video signals The video control section then checks the state of the printer engine by handling the signals with the printer engine control section and then instructs printing after which it sends the video signals The printer engine control...

Page 106: ... signal state is Low When the printer engine control section receives this signal it prepares the printer for printing by rotating the pho tosensitive drum and picking up the recording paper for example nTOP signal Top Of Page This is the vertical scanning vertical direction sync signal for the LASER beam and is used for printing the start of the image first line at an appro priate position on the...

Page 107: ...OP signal has changed to Low nVDO signals are sent successively from the 1st line of the image The LASER is turned ON when nVDO is Low and OFF when High LASER drive signals The LASER drive signal is an nVDO signal to which the LASER ON sig nal has been added LASER ON signals are required for generating the nBD signal Fig 4 30 LASER Drive Signals About the nBD and nTOP Signals As described above th...

Page 108: ...scanning start position in the Horizontal scanning direction the same for each line of the image The nBD signal is the signal generated by irradiating the LASER beam on a small mirror BD mirror at the end of the photosensitive drum and detecting it Fig 4 32 nBD Signal Scanning direction Normal When the start position has shifted partially When the start position of the entire image has shifted Dru...

Page 109: ... drum must be transferred to the recording paper During this transfer the leading edge of the image on the photosen sitive drum must be made to match the leading edge of the recording paper For this reason the nTOP signal is required for controlling the start of the image that is the scanning start position of the first line of the image The first line of the image is sent after a fixed period of ...

Page 110: ...nned on the photosensitive drum This series of operations is repeated for each line of the image at a time The photosensitive drum also rotates at a fixed speed to prevent lines of the image overlapping each other Next let s describe the functions of each component 1 Collimator lens The LASER beam emitted from the semiconductor LASER is diffused This lens corrects the LASER beam so that it becomes...

Page 111: ...am on the planes of the scanning mirror Fig 4 37 Cylindrical Lens 3 Toric lens This lens corrects the LASER beam again so that it becomes parallel Fig 4 38 Toric Lens Cylindrical lens LASER beam Scanning mirror Scanning mirror Cylindrical lens LASER beam Toric lens LASER beam Scanning mirror ...

Page 112: ...point on the photosensitive drum is used as the condensing lens Fig 4 39 Condensing Lens 4 6 Printing Process The printing process comprises the six steps shown below Fig 4 40 Printing Process fθ lens Scanning mirror LASER beam Point B Fixed scanning speed Point A Scanning mirror LASER beam Focusing lens Point B Fast scanning speed Point A Slow scanning speed 2 Exposure step 3 Developing step 1 Pr...

Page 113: ... Exposure step In this step the LASER beam draws the image area where the charge has disappeared on the photosensitive drum Fig 4 42 Exposure Step 3 Developing step In this step toner is attached to this invisible image on the photosensitive drum to change it to a visible image Fig 4 43 Developing Step Primary charging roller negative electrical charge Area where charge has disappeared LASER beam ...

Page 114: ...he recording paper to form a permanent image Fig 4 45 Fixing Step 6 Drum cleaning step In this step the remaining toner is removed from the photosensitive drum Fig 4 46 Drum Cleaning Step Drum Direction of progression Recording paper Thansfer charging roller positve electrical charge Heater Toner Pressure heat Direction of progression Recording paper Drum Recording paper Cleaner blade Toner is scr...

Page 115: ... the negative electrical charge on the photosensitive drum at an uniform value The DC bias changes proportionately to the DC bias applied to the developing cylinder Fig 4 47 Primary Charging Photosensitive drum The photosensitive drum is an important component in forming images and comprises a photosensitive layer and an aluminum substrate Gener ally an OPC Organic Photo Conductor is used as the p...

Page 116: ... and areas not irradiated to form an image on the pho tosensitive drum Of course this image cannot be seen by the human eye This invisible image is called an electrostatic latent image the area on the photosensitive drum irradiated by the LASER beam a light area and the area not irradiated a dark area Fig 4 48 Exposure In actual fact the negative electrical charge of the area irradiated by the LAS...

Page 117: ...itive drum when the electromagnetic field between the surface of the developing cylinder and the electrostatic latent image section on the surface of the photosensitive drum becomes stronger than the force of the magnetic that is attracting the toner This development is called the toner projection development Fig 4 49 Development DC bias is also applied to the developing cylinder in addition to th...

Page 118: ...s removed to improve contract There also exists a differ ence between the electrical potential of light areas and the electrical potential of the developing cylinder This difference is in a mutual relationship where the electrical potential of light areas is smaller than the electrical potential of the developing cylinder Accordingly as the developing cylinder tries to attract toner the toner retu...

Page 119: ...ugh in small amounts 4 Here excess toner cling to dark areas on the surface of the photosensi tive drum is removed to prevent fogging There also exists a differ ence between the potential of dark areas and the potential of the developing cylinder This difference is in a mutual relationship where the potential of dark areas is smaller than the potential of the develop ing cylinder As the mutual dif...

Page 120: ...gistration switches Transfer step When the recording paper is charged with the positive electrical charge from the rear surface via the transfer charging roller the positive electrical charge moves to the surface of the transfer roller As the toner has a nega tive electrical charge the toner is transferred onto the recording paper This method is called the roller transfer method After the toner is...

Page 121: ...the strength of the recording paper itself as a result of the outside diam eter of the photosensitive drum being reduced This is called curvature separation Fig 4 53 Curvature Separation As even light stock recording paper tends to wind onto the photosensitive drum the electrical charge remaining on the recording paper is removed by the static charge eliminator Photosensitive drum Recording paper ...

Page 122: ... toner melts as a result of the heat and is fixed to the recording paper by pressure Fig 4 54 Fixing Generally fluorine coated polyimide film is used as the fixing film The reason why the film is coated with fluorine is to prevent the adhesion of toner onto the fixing film Silicon rubber is used on the fixing pressure roller SURF Fixing As the fixing film is thin and has little heat capacity the t...

Page 123: ...ated range Drum cleaning step After toner transfer an extremely slight amount of toner remains on the photosensitive drum without being transferred to the recording paper For this reason the toner remaining on the photosensitive drum is removed in this step This step involves rotating the photosensitive drum and scraping off the remaining toner from the photosensitive drum to clean the surface of ...

Page 124: ...antenna sensor The voltage generated to the antenna sensor changes according to the amount of toner Toner is judged to be absent when the amount of toner falls and the output voltage of the antenna sensor falls below a certain stipulated value LED method Light is irradiated on a photo transistor on the outside of the cartridge from the LED under the cartridge Toner is judged to be absent when the ...

Page 125: ... function may not necessarily be needed if the facsimile is used only as a printer The reason for this is that a new toner cartridge should be loaded and printing should be executed again if the print image is faint or printed as blank What should we do for a facsimile If the print image is faint after the image has been received we must contact the other party and ask them to send again Alternate...

Page 126: ...of the ink and cause ink drops to be ejected to print the image by suddenly changing the state of the ink by heat generated from the heater 4 9 Printing by Bubbles The following figure shows the operating principle of BJ printing Fig 4 57 Principle of Operation of BJ Printing Ink Nozzle Heater element 1 2 3 4 5 6 ...

Page 127: ... vaporizes for form bubbles 4 The bubbles expand to maximum size and an ink drop is pressed out side the nozzle 5 The heater temperature drops and the bubble suddenly shrinks This causes the ink that was pressed outside to form into liquid 6 When the heater temperature drops further the ink drop flies out of the nozzle The ink that flies out of the nozzle is charged in the nozzle from the ink tank...

Page 128: ...ction is broadly divided into the following three parts Carriage section Purge unit BJ cartridge Fig 4 58 Printing Section Carriage Carriage belt Carriage guide shaft Carriage ribbon cable Carriage motor BJ cartridge Purge unit Paper feed motor Carriage section ...

Page 129: ...arriage drive mechanism Print deviation compensation mechanism Paper feed motor drive switching mechanism Pumping operation state detection mechanism Fig 4 59 Carriage Section Print deviation compensation mechanism Carriage drive mechanism Pumping operation state detection mechanism Paper feed motor drive switching mechanism BJ cartridge loading mechanism ...

Page 130: ...tri cal connection By this connection signals such as print signals are sent to the BJ print head The printer control section monitors the mounted state of the BJ cartridge at all times and judges that there is no cartridge if the BJ cartridge head is not electrically connected with the signal contact pad of the carriage ribbon cable for a certain period or more Fig 4 60 BJ Cartridge Loading Mecha...

Page 131: ...ting the carriage position is judged by the printer controller counting the number of motor drive pulses Fig 4 61 Carriage Drive Mechanism Print deviation compensation mechanism The carriage motor load is adjusted and the carriage position is compen sated to prevent print deviation caused by changes in the BJ cartridge weight and error during bi directional printing During detection of the home po...

Page 132: ...ol pin inside the purge unit 2 During pumping operation The pendulum gear is released by the carriage moving to the home position and pressing the control pin and the purge drive gear is cou pled with the pendulum gear Power in the reverse direction of the paper feed motor is transmitted to the purge drive gear inside the purge unit via the feed roller and pendulum gear to perform pumping Fig 4 62...

Page 133: ...ored to memory When the error is canceled the received image data in memory is printed Pumping operation state detection mechanism When the carriage moves to the home position the home position sensor switches to the sensor for detecting the pumping operation state The home position sensor detects the pumping operation state by the movement of the actuator arm that is interlocked with the pumping ...

Page 134: ...Wiping operation Maintenance jet operation Cleaning is performed automatically at the following times When the BJ cartridge is replaced When a fixed amount of time has elapsed since the previous cleaning before the power is turned ON and before printing When the ink discharge count has reached the preset count during printing Manual cleaning initiated by the user is also possible Fig 4 64 Purge Un...

Page 135: ...d from the cap the pump sucks out ink via the rubber cap and the ink is blown out to the waste ink sheet The inside of the nozzles on the BJ print head are then filled with fresh ink This operation is called pumping Pumping removes unwanted air bubbles and impurities together with ink from inside the nozzles Wiping operation The surface of the nozzles is wiped by a wiper This operation is called w...

Page 136: ...w atmospheric pressure and supply of ink to the head is prevented The ventilation holes on the cartridge cover maintain the inside of the cartridge body at a fixed pressure to prevent this phenomenon Ink sponge This sponge is soaked with ink and is contained inside the cartridge body in a compressed state Cartridge body This plastic case couples the BJ print head unit to the ink sponge Ventilation...

Page 137: ... the ink droplets leave the nozzles bubbling by remaining heat from the heater continues to dis charge ink droplets from the nozzle tips After ink droplets are ejected from the nozzles the nozzles are charged with ink again from the ink sponge Joint pipe Ink filter Flow of ink from ink sponge Signal circuit Printed circuit board Silicon plate Aluminum plate Heater plate Ink ejection hole Ink chamb...

Page 138: ...ridge separate type When the latter type of BJ cartridge has run out ink replacement of only the ink cartridge is possible Generally the ink cartridge is called the ink tank Fig 4 67 BJ Cartridges integrated type and separate type Ink cartridge ink tank BJ print head unit Separate type Integrated type ...

Page 139: ...d type BX 2 black Ink sponge Integrated type BX 3 black Ink sponge and liquid Integrated type BC 10 black Ink sponge Separate type BCI 10 black BCI 17 black BC 11e color Ink sponge Separate type BCI 11 black BCI 11 color BX 20 black Ink sponge Integrated type BC 20 black Ink sponge Integrated type BC 21e color Ink sponge Separate type BCI 21 black BCI 21 color BC 22e photo Ink sponge Integrated ty...

Page 140: ...ting ink is ejected to the optical axis between the LED light emitting section and the photo tran sistor light receiving section The presence of ink is detected by the change in photo transistor output at this time For the duration that ink is present the amount of light reaching the photo transistor decreases by the ejected ink When there is no more ink the amount of light reaching the photo tran...

Page 141: ... receiving section The presence of ink is detected from the output of the photo transistor at this time For the duration that ink is present the light is absorbed by the footer mark and does not reach the photo transistor When there is no more ink the footer mark is not printed and so light is reflected on the recording paper white and reaches the photo transistor Fig 4 69 Reflecting type Photo in...

Page 142: ... by the ink and does not reach the photo transistor When there is no more liquid ink light is reflected onto the reflector plate white provided inside the ink tank and reaches the photo transistor Note however at the point where the ink tank runs out of liquid ink ink still remains absorbed by the ink sponge and the ink tank has not completely run out of ink Counting of the number of ink ejects is...

Page 143: ...45 5 1 Modulation and Demodulation 5 45 5 2 Shift and Modulation Methods 5 46 5 3 Modulation Methods up to 9600 bps 5 47 5 4 High speed MODEMs above 14400 bps 5 55 5 5 V 17 V 33 MODEM Technology 5 55 5 6 V 34 MODEM Technology 5 73 6 TRANSMISSION CONTROL PROCEDURES 5 89 6 1 Outline of Transmission Control Procedures 5 89 6 2 Signal Types 5 90 6 3 Basic Transmission Control Procedure 5 91 6 4 Proced...

Page 144: ...smission speed and image quality G3 facsimiles have the following features Features Image data is handled as groups of black and white dots Coding and high speed modulation are adopted Various and diverse functions can be used as binary signals are adopted for control procedural systems When G3 facsimiles first appeared on the market they transmitted a A4 size standard document in about one minute...

Page 145: ...de The resulting data is digital coded data 6 The coded data is converted to binary image data by decoding 7 The binary image data is sent to the recording section to be printed This chapter describes 3 through 6 1 and 2 are described in Chapter 3 Reading Section and 7 is described in Chapter 4 Recording Section 3 1 Structure of Image Signals Reading of the image is performed in each scanline in t...

Page 146: ...tructure of Image Signals EOL End Of Line A coded scanline in the horizontal scanning direction is transmitted con secutively from the 1st line The end of each scanline is appended with a 1728 dots 1145 lines 297 mm 210 mm Horizontal scanning line density 8 dots mm Vertical scanning line density 3 85 lines mm Horizontal scanning direction Vertical scanning direction Standard A4 document Document f...

Page 147: ...ter than the minimum transmis sion time described later when the time obtained by combining the data and EOL is shorter than the minimum transmission time Fills are a string of 0 bits and their length is not fixed These signals are removed from the image signal at reception 3 2 Transmission Time Transmission time is the time required to transmit image signals To determine the transmission time the...

Page 148: ...e required to process each single line at transmission and reception is defined as the minimum trans mission time MTT for expressing the processing capability of that machine If the transmitting side transmits without taking into consideration the pro cessing capability of the receiving side recording on the receiving side will not be able to keep up with reception and communications will not be p...

Page 149: ...machine that allows one page s worth of image data to be received to memory for image reception the image can be received without any fills as there is no need to worry about the delay in print processing at reception Table 5 1 Types of Minimum Transmission Times Minimum transmission time ms Reception Transmission Standard Fine 20 20 20 40 40 40 10 10 10 5 5 5 10 5 20 10 40 20 0 0 0 MTT EOL MTT EO...

Page 150: ... 9600 bps MODEM it takes three minutes 26 seconds and when it is transmitted using a 14400 bps MODEM it takes two minutes 17 seconds Without coding transmission of a standard A4 document will take longer than one minute Why then can the transmission time be reduced with coding Normally a document transmitted by a facsimile has lots of white areas Text that is written in these white areas take on m...

Page 151: ...allocate codes with high efficiency to these runs to reduce the size of the image information This is called redundancy suppression coding or redundancy compression coding From here on in this chapter let s sim ply refer to this as coding Fig 5 7 Example of Document Although various coding schemes are possible the most efficient one is the Huffman scheme A slightly modified version of this scheme ...

Page 152: ...of these coding schemes in order 4 2 MH Coding Scheme One dimensional Coding Scheme The following describes an example using an A4 size document If a document is viewed in unit of single lines text areas are black and areas without text are white All of the scanlines are expressed as a group of white runs and black runs The length of these runs is called the run length The MH coding scheme codes e...

Page 153: ... MH coding These processes are nor mally performed by the CPU and the resulting image data is stored to memory That data is then sent to the MODEM where it is modulated and then transmitted to the telephone line On the receiving side the procedure is completely reversed and the original data is restored by demodulation Fig 5 9 Procedure for Image Data Processing on the Transmitting Side Let s try ...

Page 154: ...is 0 to 63 Coding when the run length is 64 or more In this case coding is performed by a make up code which shows the larg est run length without exceeding the run length of that run Next the dif ference between the actual run length and the length of the make up code is coded by a terminating code Fig 5 12 MH Coding When The Run Length is 64 or More White run length 5 Scanline after conversion t...

Page 155: ...f data compression is to reduce the transmission time considerably Image Data Unsuitable for Compression If coding is performed this does not necessarily mean that the size of the information of any document can be compressed to reduce the transmis sion time The effect of coding is reduced on documents where short white runs and short black runs occur alternately for example halftone photo graphs ...

Page 156: ...10011 8 000101 9 10100 9 000100 10 00111 10 0000100 11 01000 11 0000101 12 001000 12 0000111 13 000011 13 00000100 14 110100 14 00000111 15 110101 15 000011000 16 101010 16 0000010111 17 101011 17 0000011000 18 0100111 18 0000001000 19 0001100 19 00001100111 20 0001000 20 00001101000 21 0010111 21 00001101100 22 0000011 22 00000110111 23 0000100 23 00000101000 24 0101000 24 00000010111 25 0101011 ...

Page 157: ...10101 46 00000101 46 000001010110 47 00001010 47 000001010111 48 00001011 48 000001100100 49 01010010 49 000001100101 50 01010011 50 000001010010 51 01010100 51 000001010011 52 01010101 52 000000100100 53 00100100 53 000000110111 54 00100101 54 000000111000 55 01011000 55 000000100111 56 01011001 56 000000101000 57 01011010 57 000001011000 58 01011011 58 000001011001 59 01001010 59 000000101011 60...

Page 158: ...0001001100 832 011010010 832 0000001001101 896 011010011 896 0000001110010 960 011010100 960 0000001110011 1024 011010101 1024 0000001110100 1088 011010110 1088 0000001110101 1152 011010111 1152 0000001110110 1216 011011000 1216 0000001110111 1280 011011001 1280 0000001010010 1344 011011010 1344 0000001010011 1408 011011011 1408 0000001010100 1472 010011000 1472 0000001010101 1536 010011001 1536 0...

Page 159: ...is performed Two consecutive scanlines are expanded as shown in Fig 5 15 When the black and white changing pixels shown by black dots of each scanline are compared it can be seen that they have shifted to the laterally Data is compressed by comparing the black and white changing pixels with the previous scanline and by coding this shift Due to the fact that changes in the two dimensional pixels ar...

Page 160: ... table are used for the following reason 1 By the MR coding scheme coding must be started from completely describing the initial line Otherwise subsequent lines cannot be coded using the data that indicates the presence of changes 2 When a document is transmitted by only the MR coding scheme the receiving side facsimile sometimes cannot correctly decode the scan line due to an error occurring midw...

Page 161: ...ferenced to at this time is called the reference line Fig 5 16 Transmission Error and Parameter K Table 5 4 Parameter K Vertical Scanning Line Density Parameter K Standard 3 85 lines mm 2 Fine 7 7 lines mm 4 Super fine 15 4 lines mm 4 Ultra fine 15 4 lines mm 4 In case of parameter K 4 Without parameter 4 lines Transmission error Subsequent lines cannot be correctly decoded 4 lines Transmission er...

Page 162: ...ng pixels Before we start explaining the coding procedure let s define what a changing pixel is A changing pixel is defined as a pixel whose color i e black or white is different from that of the previous pixel on the same line a0 The reference or the starting changing pixel on the coding line At the start of the coding line a0 is placed on an imaginary white changing pixel situated just before th...

Page 163: ...below an appropriate code word is selected from the code table shown in Table 5 5 This proce dure is shown in the flow chart in Fig 5 22 Step 1 1 When the pass mode is detected coding is performed using the word 0001 Table 5 5 After this pixel a0 just under b2 is regarded as the new starting pixel a0 for the next coding operation 2 If the pass mode is not detected then proceed to Step 2 Step 2 1 D...

Page 164: ... been coded This may be coded as a1 or a2 Also if b1 and or b2 are not detected at any time during the coding of the line they are positioned on the imaginary chang ing pixel situated just after the last actual pixel on the reference line 4 3 5 Coding modes One of the three coding modes is selected according to the coding proce dure 1 Pass mode This mode is stipulated when b2 lies to the left of a...

Page 165: ... cal mode has been performed the position of a0 is moved to a1 See Fig 5 21 3 Horizontal mode When this mode is detected both the run lengths a0a1 and a1a2 are coded using the code words H M a0a1 M a1a2 H is the flag code word 001 taken from the MR code table Table 5 5 M a0a1 and M a1a2 are code words which represent the length and color of the runs a0a1 and a1a2 respectively and are coded from th...

Page 166: ...01 Horizontal a0 a1 a1 a2 H 001 M a0 a1 M a1 a2 1 1 Horizontal mode code M shows the MH code words in Tables 5 2 and 5 3 Vertical a1 just under b1 a1 b1 0 V 0 1 a1 to the right of b1 a1 b1 1 VR 1 011 a1 b1 2 VR 2 000011 a1 b1 3 VR 3 0000011 a1 to the left of b1 a1 b1 1 VL 1 010 a1 b1 2 VL 2 000010 a1 b1 3 VL 3 0000010 ...

Page 167: ...ust before the 1st pixel Start First line of K lines EOL 0 End of line End of page End NO YES NO YES NO YES Detect a1 Detect b1 Detect b2 b2 to the left of a1 NO YES Pass mode coding Place a0 just under b2 RTC Place a0 on a2 a1 b1 3 Detect a2 Horizontal mode coding YES Vertical mode coding Place a0 on a1 NO EOL 1 ...

Page 168: ... for the coding example Table 5 6 Explanatory Notes for MR Coding Example Item Remarks EOL 1 Shows that the following coded line is MH coded EOL 0 Shows that the following coded line is MR coded 1728W Shows that the white run has a run length of 1728 1B Shows that the black run has a run length of 1 V 0 Shows that the vertical mode has a relative distance value of 0 H Shows that coding is in horiz...

Page 169: ...V 0 V 0 V 0 V 0 EOL 0 1 0001 1 1 1 1 1 1 0000000000010 MR coding V 0 H M 1 M 4 V 0 V 0 V 0 V 0 V 0 V 0 1 001 010 1011 1 1 1 1 1 1 EOL 1 0000000000011 3rd line 6th line MR coding H M 3 M 1 H M 4 M 1 H M 3 M 1 001 1000 010 001 1011 010 001 1000 010 MH coding 3W 1B 4W 1B 3W 1B 5W 1B 1709W 1000 010 1011 010 1000 010 1100 010 011000 00000100 2nd line 4th line 5th line 7th line 8th line MR coding V 0 V ...

Page 170: ... somewhat resembles the MR coding scheme By MMR coding starts from a white line and there are no restrictions in parameter K In other words the initial line is taken to the be the reference line and only differences from the previous line are coded by MR right until the end of the page For this reason as a condition for use of MMR MMR is limited to instances where error free communi cations can be...

Page 171: ...ume will not exceed the volume of original image information after compression and when decoding the image can be completely re assembled to its original condition in the same way as with conventional MR MMR A coding scheme such as this that allows the original image to be com pletely restored is called a reversible scheme and a coding scheme that does not allow the original image to be completely...

Page 172: ...mprove the resolution is forwarded The previous low resolution image is decoded on the receiving side with this informa tion and following this the high resolution image is displayed on top of the previous low resolution image It is easy to quickly recognize the original image in the process of display ing the image from low resolution to high resolution in order by using this scheme with a CRT di...

Page 173: ...h resolution layers to perform encoding decoding In the Single Pro gression Sequential Bi level Image Compression Scheme encoding is done in units of horizontal bands a number of lines called stripes and is performed from left to right top to bottom this condition is called sequen tial and in one resolution layer single layer In this scheme the encoding is done in stripe units so it is completed w...

Page 174: ... will not increase and if the prediction is off the amount of encoding increases so the increase in prediction accuracy of this study table is very important An outline of the encoding procedure is shown below Fig 5 26 Encoder and Flow of JBIG Encoding ENCODER Comparison of current and previous lines Image data input TYPICAL PREDICTION Output of match no match ARITHMETIC ENCODING Output of image d...

Page 175: ... When the lines are judged to not match the line is said to be not typical When the very first line of an image is predicted the background color is used as the previous line 2 In the model template the combination 10 bit pixel pattern of 10 pixels is output to the arithmetic encoding section using the template shown below inside the bold outline All of the 10 bit pixel patterns inside this templa...

Page 176: ...able is corrected learned to a new prediction value and status number which will be used when the same pixel pattern is found again By learning in this way the probability of the study table matching the next time is increased and the need for encoding decreased Fig 5 28 Positions of Pixels in Model Template Table 5 8 Study Table Initial values Pixel pattern in the model template Predicted value o...

Page 177: ... 30 9 0 65 4D04h 80 66 0 49 0706h 79 50 0 106 50E7h 108 107 0 50 05CDh 48 51 0 107 4B85h 109 103 0 51 04DEh 50 52 0 108 5597h 110 109 0 52 040Fh 50 53 0 109 504Fh 111 107 0 53 0363h 51 54 0 110 5A10h 110 111 1 54 02D4h 52 55 0 111 5522h 112 109 0 55 025Ch 53 56 0 112 59EBh 112 111 1 56 01F8h 54 57 0 ST Status number in the study table LSZ Probability estimation value range for inaccurate predictio...

Page 178: ... The status ST is 0 so the probability estimation table is consulted and the next status is moved to 1 The prediction for the next pixel remains white Fig 5 30 Study Table Study Example 2 Study table for current pixel Probability estimation table Pixel pattern 000h 001h 002h Predicted value 0 white Actual value 1 black Accurate Inaccurate Inaccurate 0 0 0 Study table for next pixel 000h 001h 002h ...

Page 179: ... section there is no conversion table for encoding as is the case in encoding with conventional MH and MR Using the LSZ probability estimation value of an inaccurate prediction the form of a range of the probability estimation table and the accuracy inaccuracy of the predicted value as a base encoding is done by showing the posi tion of the progress of the prediction on an integer line between 0 t...

Page 180: ...with inaccurate predictions an additional encoding bit will be necessary to show the position of the inaccuracy in detail and thus the amount of encoding will increase and the rate of compression decrease In this way the study table learns in order to increase the rate of accurate predictions and to reduce the amount of encoding and raise the compression rate during the encoding process and then c...

Page 181: ...t it is over decimal 8000 decimal 1000 added An accurate range will be MPS and an inaccurate range will be LPS Fig 5 32 When Predictions are Continually Accurate In this case the encoding 1 bit is output for the first time when Range A falls becomes less than 8000 in the 21st pixel The following output encoding is shortened and its compression increased Pixel No encoded LPS MPS RANGE Range A2 Rang...

Page 182: ...l Image Entity and is constructed from the Bi level Image Header BIH section and the Bi level Image Data BID section shown in the figure below Fig 5 34 BIE Construction Diagram Document width XD Document length YD Stripe length L0 JBIG encoding JBIG encoded Document BIH BID SDE Header SDE SDE BID BID BIE Stripe Stripe Stripe Floating marker code Floating marker code Floating marker code BIE Bi lev...

Page 183: ... Bi level Image Header Symbol Meaning Parameter Reference DL Initial layer to be transmitted 0x00 fixed D Number of differential layers 0x00 fixed P Number of bit planes 0x00 fixed FILL Fill 0x00 fixed XD Horizontal image size at layer D 0xXXXXXXXX Document width No of bits YD Vertical image size at layer D 0xXXXXXXXX Document length No of bits L0 Lines per stripe at the lowest resolu tion 0xXXXXX...

Page 184: ...1 0 3 lines 1 2 lines VLENGTH Indication of possible use of NEWLEN marker segment 1 bit 0 1 Use of 0 NEWLEN not allowed Use of 1 NEWLEN allowed TPDON Use of TP for Typical Prediction for differential layers 1 bit 0 fixed TPBON Use of TP for base layer 1 bit 0 1 0 OFF 1 ON DPON Use of Deterministic Prediction 1 bit 0 fixed DPPRIV Use of private DP table 1 bit 0 fixed Has meaning when DPON is 1 DPLA...

Page 185: ...pear any where ATMOVE AT move 0x06 Designates from which line the movement of the AT pixel starts and where it wil move to COMMENT Private comment 0x07 An optional comment may be added NEWLEN New length 0x04 Redefine the document length Only usable when VLENGTH ON RESERVE Reserve 0x01 Only usable for characteristic use 2 Stripe data section PSCD Protected stripe encoding data The actual image data...

Page 186: ...te units SDNORM Stripe data completion 0x02 Shows the completion of stripe data SDRST The reset at completion of stripe data 0x03 Shows the completion of stripe data Everything including the study table and the ATMOVE are reset When the image data encoding is 0xFF it is imperative to attach 0x00 after the image data encoding 0xFF in order to distinguish ESC 0xFF ESC 0x02 ESC 0x03 ...

Page 187: ...fer according to the MODEM in use 5 1 Modulation and Demodulation On a facsimile the digitally coded image data varies the analog carrier wave Converting digital signals to analog signals in this way is called modulation When modulation processing is performed the digital information is moved onto the changes in the carrier wave Changing the carrier wave in this way is called modulation by digital...

Page 188: ...smitted and received by the MODEM Bandwidth of Telephone Line There is also another important point in data transmissions using a public switched telephone line That is the problem of the bandwidth of the tele phone line The actual bandwidth of a public switched telephone line is between 300 Hz and 3400 Hz MODEMs assure facsimile data transmis sion within this bandwidth by using the carrier wave o...

Page 189: ... In this example digital 0 s is expressed by a signal of 1850 Hz and digital 1 s is expressed by a signal of 1650 Hz The length of frequency components that shows each numeri cal value is 1 300 seconds In other words 300 frequency components are transmitted in one second As each component is equivalent to a single bit the data transmission speed using FSK becomes 300 bps This type of FSK system is...

Page 190: ...ative position between the carrier wave and the phase Fig 5 39 Carrier Wave and Phase As can be seen from this figure the same start point is returned to if the 360 phase is advanced along the signal whichever point is taken as the start point In other words the position of 360 indicates exactly the same point as the position of 0 on the signal Phase change shows the size of the phase by which the...

Page 191: ... a two dimensional diagram in which the carrier wave shows the phase of 360 Diagram axes shows the amplitude range of the signal at each respective phase The num ber of these axes is either four or eight depending on which PSK method is adopted Fig 5 41 4 phase and 8 phase Spatial Diagram 2 2400 bps PSK methods By this PSK method on a facsimile four relative phase changes are used to express digit...

Page 192: ...bps ITU T recommendation V 27 ter ITU T recognizes PSK methods that transmit data at a speed of 2400 bps and related standards are called ITU T recommendation V 27 ter 3 4800 bps PSK methods 4800 bps modulation PSK methods are also used in facsimile data trans missions By this PSK methods eight relative phase changes are used to express dig ital signals If we use the spatial diagram in Fig 5 44 be...

Page 193: ...hods can be used to achieve transmission speeds of 7200 bps or higher If we fully consider the 4800 bps 8 phase system described above we can understand how this can be achieved For exam ple if the modulation speed is increased to 2400 baud then a transmission speed of 7200 bps can be obtained However transmission speeds this fast are not used in facsimile transmission There are two reasons for th...

Page 194: ...arrier wave in the same way as in the PSK method Fig 5 45 shows the spatial diagram of the QAM method Here too we can see that the relative changes at 0 45 90 135 180 225 270 and 315 are used and further that each of the phase changes indicates a tribit The figure also shows the fact that the carrier wave has two relative amplitudes These amplitudes are each identified as large amplitudes whose in...

Page 195: ...AM methods differs in respect that the carrier wave does not carry any information In other words the initial bit of the quad bit is fixed to 0 and is a so called unwanted bit The remaining bits are used to change the phase and the modulation speed is 2400 baud For this reason the data transmission speed becomes 7200 bps 7200 bps QAM systems are also called ITU T recommendation V 29 in the same wa...

Page 196: ...hanges When this is performed demodulation can no longer be executed due to the influence of line distor tion Fig 5 47 illustrates this Fig 5 47 QAM Method and Influence of Line Distortion For this reason only eight phase changes are used in QAM methods The QAM method provides a target for each phase change and amplitude change So that these change points are regarded as valid QAM signals they mus...

Page 197: ...and the 33600 bps MODEM recommended in V 34 5 5 V 17 V 33 MODEM Technology V 17 V 33 MODEMs recommended by ITU T are capable of transmitting data at a high speed of 14400 bps Until this recommendation was reached several 14400 bps MODEMs using existing technology were put onto the market PARADYNE Inc first put a MODEM onto the market in 1980 and was followed by CODEX Inc the following year in 1981...

Page 198: ...n conducted since 30 to 40 years ago This all began with Shannon in 1948 who announced that an error correction code capable of reducing the error rate exists after decod ing is performed on a communications path that contains noise Of the numerous error coding schemes trellis coding and Vitterbi decoding that are currently used in V 17 MODEMs are suited to correction of random errors and are know...

Page 199: ... data 00 is output and the state remains at A When 1 is added to the input data coded data 11 is output which means that the state will shift to state B In other words from state A the state shifts only to state A or to state B The shift in states of other states B C and D also have the same nature Fig 5 50 Shift in States of Convolutional Coder In Fig 5 50 when input data is 0 for each of the int...

Page 200: ...d as a decoding scheme for trellis coding Before we dis cuss the Vitterbi algorithm let s discuss maximum likelihood decoding on which the Vitterbi algorithm is based Maximum likelihood decoding is a decoding scheme when a coded data string output from the coder passes along the communications path and is received where the most reliable looking coded data is judged and decoded by calculating all ...

Page 201: ... exponentially when the receive data strings have increased So a coder that calculates all Hamming distances one by one will be a massively large scale circuit Whereas Vitterbi decoding is a decoding scheme that suppresses and minimizes the number of calcula tions required for selecting the most reliable looking coded data string to only the number of states that are determined by the structure of...

Page 202: ...ches arrived at from step i and the distance that is pathmetric up to step i corresponding to this is calculated and compared Whichever of the paths smaller than the sum of the distance of these two is taken to the survival path in step i 1 The sum of the distance in the survival path is taken to the new pathmetric in step i 1 3 The survival path and pathmetric in each of the states in step i 1 ob...

Page 203: ...an distance Though the Hamming distance is generally expressed as a Euclidean distance the Euclidean distance is expressed as an analog amount Conversion of the analog amount of this Euclidean distance to a digital amount is called soft judgment Vitterbi decoding ai 1 c a ai 1 Path memory A bi 1 bi 1 Pathmetric M a1 c1 a a a b c b Pathmetric M Pathmetric M Branchmetric λ Branchmetric λ Comparison ...

Page 204: ...line noise generated on the transmission path into consideration and adopts an error correction mode that uses Euclidean distance in other words the distance between satellite points for the receive signals as the method for judging the receive data Essentially Euclidean distance is an analog amount and a precision ana log circuit is required to achieve trellis coding Vitterbi decoding using the E...

Page 205: ...terminal device is sorted into data symbols every six bits by the parallelizing circuit and is input to the trellis coder In the coder first of all specific two bits Q1n and Q2n from among six bits Q1n to Q6n that were input are input to the differential coder to be differentially coded After the two bits Q1n and Q2n are input to the differential coder they are differentially coded as shown in Tab...

Page 206: ... send data Q3n Q4n Q5n and Q6n that are not coded by the mapping circuit In other words the coding ratio is 6 7 as the trellis coder in Fig 5 53 outputs seven bits of coded data on six bits of input data Table 5 11 Differential Coding in V 17 Input Advance Input Output Q1n Q2n Y1n 1 Y2n 1 Y1n Y2n 0 0 0 0 0 0 0 0 0 0 1 1 0 1 0 1 0 0 1 1 0 1 0 1 0 0 0 0 1 1 1 1 0 0 1 1 0 1 0 1 0 0 1 1 1 0 1 0 1 1 1 ...

Page 207: ...111100 0110010 0011100 1110010 0001100 0111001 0100101 0011001 1000101 0001001 0110000 0101110 0100000 0101011 0010111 1101011 1101110 1000000 1010111 1111100 0010010 1011100 1010010 1111001 1100101 1011001 1110000 1001110 1100000 1001011 0000111 0000010 0000110 0000011 1001111 1100100 1001010 1011101 1100001 1111101 1010110 1011000 0010110 1010011 1101111 0010011 0101111 1000100 1101010 0100100 0...

Page 208: ...er the Euclidean distance between output signals that are coded as described above must be made as large as possi ble With a trellis coder stipulated in V 17 the coded output data is three bits Y0n Y1n and Y2n and are mapped so that the distance between sig nals in the eight states expressed by these three bits becomes larger For this reason the seven bits that express each of the signal points of...

Page 209: ... Fig 5 57 shows the finally selected point as a large dot If we focus on only the 16 points relating to point A selected here it can be seen that the minimum distance between each of the 16 points will be mapped to become twice the root extraction of 2 of the min imum distance between each of the 128 points C7 B6 C3 C1 A1 D3 F9 H0 H7 F4 H3 F8 H1 A6 D5 A4 D13 A8 C5 E5 G2 E13 G10 B2 C11 B10 A14 H15 ...

Page 210: ...ase modulation system is performed in other words the data is replaced with the phase change of the carrier signal before it is transmitted By this system when an instantaneous phase change has occurred an error will occur at that time However data from then on will not be affected In V 17 the differential coder that is used as a pre stage to the trellis coder is mounted for such kind of purpose a...

Page 211: ...bi decoding that uses the Euclidean distance this branchmetric is calculated as the Euclidean distance between the received signals and each signal point At this stage a single branch having the smallest distance is deter mined in the 16 signal point group for each of A to H For example the signal points for A are 16 points A1 to A16 Of these 16 points a certain point is determined In other words ...

Page 212: ...29 and work for standardization as a MODEM having fallback speeds of 12000 bps and 9600 bps was advanced However other work groups in ITU T were already studying the transmission speeds of already recommended MODEMs with a view to reducing that speed as much as possible and so the fallback speed was determined at only 12000 bps in keeping with that spirit This fact means that compatibility with V ...

Page 213: ...ue in the deliberation became whether to select 1700 Hz the carrier frequency of a V 29 MODEM or to select the 1800 Hz of the V 32 MODEM family as the car rier frequency on a recommendation V 33 MODEM As V 33 is positioned as an extended version of the V 29 MODEM there was a proposal from various countries that the carrier frequency should be selected as 1700 Hz However there was also a proposal t...

Page 214: ...circuits of frequency 3000 Hz that are frequently seen in submarine cable systems used exclusively for international lines As a result of deliberation a data transmission test by an 1800 Hz carrier fre quency MODEM was conducted via a submarine cable system mainly between ATT in the United States and KDD Kokusai Denshi Denwa Company Ltd in Japan over a 3000 Hz band telephone line As a result of th...

Page 215: ...ptimizing the modem operation according to the line condition The V 8 protocol V 34 pre protocol and post protocol use full duplex transmission to speed the processing Fourteen image transmission speeds 3 are available 33600 31200 28800 26400 24000 21600 19200 16800 14400 12000 9600 7200 4800 and 2400 bps The modulation speed baud rate 4 can be selected from among 2400 3000 and 3200 symbols sec re...

Page 216: ... V 17 or a lower protocol is selected 2 If the transmission speed is set to 14400 bps or lower the V 8 protocol is not executed and V 17 or a lower protocol is selected 3 After the V 21 protocol is selected first it can be changed to V 8 or V 34 See Fig 5 60 4 When the V 34 protocol begins it falls back within the V 34 protocol but it does not fall back to the V 17 mode or lower ...

Page 217: ...ion end procedure S S A NSS V 8 V 34 Declares the usable modulation mode Declares that V 34 capability exists on each machine and transfers the V 34 procedures with phase 2 After declaring the modem s modulation speed capacity etc to each machine the receiving side determines the modulation speed based on the results of an probing signal output by the transmitting side The transmitting side output...

Page 218: ...bbre viation Meaning Remarks Calling tone CNG 1100 Hz tone signal specified by T 30 to identify an automatic calling fax machine Call menu signal CM Indicate an available modulation scheme V 21 V 27ter V 29 V 17 or V 34 Modulated by V 21 L 1 CM terminator CJ Indicate JM signal detection and CM sig nal termination Modulated by V 21 L 1 Call indicator signal CI Indicate the general transmission func...

Page 219: ... Indicate the terminal type such as a fax machine and an avail able modulation scheme in response to the available modula tion scheme reported by the CM from the transmitter Modulated by V 21 H 1 1 V 21 L Low frequency channel defined by V 21 recommendation 1080 100 Hz 980 Hz 1 1180 Hz 0 Transmission speed 300bps V 21 H High frequency channel defined by V 21 recommendation 1750 100 Hz 1650 Hz 1 18...

Page 220: ...y transmission function two frequency bands used to measure line characteristics and request adjustment Transmission speed 600bps Tone B B Modem synchroniza tion with a 1200 Hz tone signal The phase of the B signal is inverted 180 degrees from the phase of the B signal Tone B B Probing signal L1 L1 Tone signal for analyz ing line characteristics by probing Probing Measurement of line characteris t...

Page 221: ...a tion with a 2400 Hz tone signal The phase of the A signal is inverted 180 degrees from the phase of the A signal Tone A A INFO sequence INFO0h Report the pre empha sis filter and baud rate used for data transmis sion based on the result of analysis of the prob ing signal Transmission speed 600bps Transmitter Signal Abbre viation Meaning Remarks S signal S Short training The phase of S is shifted...

Page 222: ...ted Transmitter receiver Signal Abbre viation Meaning Remarks PPh signal PPh The other modem uses this signal to train the equalizer ALT signal ALT Modulation parameter MPh Indicate the image transmission parame ters such as maximum data signal speed con trol channel data sig nal speed trellis coding type pre coding type and baud rate E sequence E 20 bit sequence of binary 1 s ...

Page 223: ...TSI Report the transmitter telephone number Digital com mand signal DCS Instruct the available mode 1 Declare to switch to high speed protocol Transmit 1 s Receiver Signal Abbre viation Meaning Remarks Non standard facilities NSF Report functions not recommended by ITU T user s ID manufac turer code etc Called sub scriber identi fication CSI Report the receiver telephone number Digital identi fica...

Page 224: ...procedure Training is performed with the parameters set in phase 4 The transmission speed is 1200bps Image data Transmit image data Transmitter Signal Abbre viation Meaning Remarks S signal S Short training The phase of S is shifted from the phase of S S signal S PP signal PP The other modem uses this signal to train the equalizer Sequence B1 B1 Scramble data frame transmitted at the end of start ...

Page 225: ...Sh signal Sh ALT signal ALT E sequence E End of proce dures PPS EOP One page is transmit ted Flag flags Maintain synchroniza tion 7E H Disconnect signal DCN Disconnect the line Receiver Signal Abbre viation Meaning Remarks Sh signal Sh Short training Sh signal Sh ALT signal ALT E sequence E Flag flags Maintain synchroniza tion 7E H Message con firmation MCF Indicate that the receiver has received ...

Page 226: ...t detect the CM signal while sending the ANSam signal it sends the DIS signal containing the V 8 protocol declaration The transmitter sends the CI signal to request the receiver to send the ANSam signal again to move to V 8 protocol Fig 5 60 Late Start ANSam JM CM CJ Connected to the line DIS DIS CNG DIS cannot be detected CI ANSam TX RX NSF CSI NSF CSI ...

Page 227: ...itter sends image data then the PPS MPS signal in the same as for the T 30 protocol The receiver sends the MCF signal to receive the next page Fig 5 61 Between page Sequence S PP B1 Image data 1 ALT Sh Sh E flags flags ALT Sh Sh flags E Image data TX RX PPS MPS MCF S Turn off Turn off ...

Page 228: ...nal and the transmitter sends the DCS signal to change the mode Fig 5 62 Mode Change S PP B1 Image data 1 ALT Sh Sh E flags flags ALT Sh Sh flags E Image data TX RX PPS EOM MCF S NSS DCS flags NSF CSI flags CFR flags DIS TSI When Canon fax machines communicate with each other a special procedure is used so this protocol is omitted Turn off Turn off ...

Page 229: ...nal in response to the Sh signal from the transmitter The image transmission speed is then determined by the MPh sequence sent from both modems Fig 5 63 Image Transmission Speed Change from the Receiver S PP B1 Image data 1 ALT PPh E flags PPR flags Sh PPS NULL flags Image data ALT ALT MPh MPh E MPh MPh TX RX Sh S PPh Turn off Turn off ...

Page 230: ... returns the PPh signal to the transmitter The image transmission speed is then determined by the MPh sequence sent from both modems Fig 5 64 Image Transmission Speed Change from the Transmitter S PP B1 Image data 1 MPh ALT E flags MCF flags flags PPh ALT PPS EOM flags E Image data MPh MPh MPh NSF CSI TSI flags CFR flags TX RX S PPh DIS DCS Turn off Turn off ...

Page 231: ... facsimiles 6 1 Outline of Transmission Control Procedures When transmission is performed on G3 facsimiles first the signal of the receiving side is asked for to verify the performance and functions of the other party Next the mode to transmit is notified and the coded image is sent When transmission of the image ends the receiving side is notified as to whether there is another page after that pa...

Page 232: ...ulation system rec ommended in ITU T recommendation V 21 Binary signals have a function for checking for errors in the transmitted data 3 Image signal On a G3 facsimile image signals are coded by coding schemes such as MH and MR The image signal modulation system and the transmission speed differ according to the MODEM in use Image signals are transmit ted at data speeds within the range 2400 bps ...

Page 233: ... procedure with spe cific parts of the overview in Fig 5 65 extracted for explanatory purposes Call CFR TCF DCS CNG CNG DIS DIS CED RTC Training Message EOP MCF DCN Training Response Line check Image of one page End of image Disconnect line Ready to receive 6 3 7 6 3 6 6 3 5 6 3 4 Training pre message response 6 3 3 Receive command 6 3 2 Initial identification 6 3 1 6 3 8 Other control signals Lin...

Page 234: ...nd returns CED CNG Transmission Reception Tonal signal This signal notifies the other party that the facsimile is an auto dial fac simile CNG can be output even on manual transmission transmitters Some receiver models have a function for switching to the facsimile when CNG is received CED Transmission Reception Tonal signal This signal notifies the other party that reception is automatic CED can a...

Page 235: ...CSI and DIS are repeatedly transmitted for a fixed period of time until DCS is returned NSF and CSI are option signals They are described in 6 7 Option Signals described later DIS Transmission Reception Binary signal This signal communicates to the other party that the function is a stan dard function recommended by ITU T mandatory Communicates the recording paper size transmission speed MTT cod i...

Page 236: ...nds the DCS Fig 5 68 Receive Command NSS and TSI are option signals They are described in 6 7 Option Signals described later DCS Transmission Reception Binary signal This signal instructs the other party to receive in the possible communi cations mode selected from the content of the received DIS manda tory Communicates the recording paper size transmission speed MTT cod ing scheme recording resol...

Page 237: ...s mitting at the image transmission speed and is performed for success fully receiving the following TCF For details see 6 5 Training TCF Transmission Reception Same modulation signal as image signal This test signal transmits a constant signal at the transmission speed used for sending the image before the actual image is transmitted to ver ify that it can be transmitted successfully This signal ...

Page 238: ...ge Transmission Training Transmission Reception Same modulation signal as image signal This signal is for performing equalizing of the MODEM when transmis sion is performed at the image transmission speed Message Transmission Reception Image signal Coded image signal RTC Transmission Reception Same modulation signal as image signal This signal is added after the final line of the image signal is c...

Page 239: ...he next document is prepared or when the transmission mode is to be changed In this exam ple EOP is transmitted as the image data is only one page MPS and EOM are also transmitted Fig 5 71 Post message Commands EOP Transmission Reception Binary signal This signal shows that transmission of images of one page is complete and that the next document is not prepared Calling Side transmitter Called Sid...

Page 240: ...ion of a single page In this example MCF is transmitted as the page was successfully received RTP and RTN are also transmitted Fig 5 72 Post message Responses MCF Transmission Reception Binary signal Shows that the image was successfully received and that the next docu ment can be received immediately Calling Side transmitter Called Side receiver Preamble RTC EOP MCF Preamble Message Training ...

Page 241: ...ls These signals are for disconnecting the line and do not require a response from the other party DCN Transmission Reception Binary Signal Signal for instructing disconnection of the line DCN MCF EOP Calling Side transmitter Called Side receiver Preamble Preamble Preamble Line disconnected Line disconnected ...

Page 242: ...hen multiple sheet doc uments are to be transmitted and the next page of the document is to be transmitted at a different resolution MPS or EOM is used in these cases These EOP MPS and EOM are collectively referred to as Q signals Fig 5 74 Example of Communications by Difference in Q Signals Response Dial Call CFR TCF DCS CNG CNG DIS CED RTC Message Q MCF DCN Calling Side transmitter Called Side r...

Page 243: ...rom the receiver the next page of the document is transmitted EOM EOM is used where there is another document and that document is to be transmitted in a different com munications mode as the present page for example when transmitting documents containing small size text in the fine mode By EOM DIS on the receiver is verified again and the communications mode is com municated by DCS to the receivi...

Page 244: ...mit image signals correctly If image signals are transmitted immediately after training errors may occur in the image signals when training is not performed properly Following training TCF a check as to whether training has been per formed correctly is transmitted at the same transmission speed as the image signals A TCF is a signal of continuous 0 lasting about 1 5 sec onds 6 5 2 When TCF can be ...

Page 245: ...returned when TCF cannot be successfully received even if fallback is repeated the transmitting side judges that communica tions is not possible on the current line and the communications ends in error Fig 5 75 Training FTT TCF DCS CNG CNG DIS DIS CED RTC EOP MCF DCN At FTT Dial Call Response Calling Side transmitter Called Side receiver Training Training Message At CFR Line disconnected Line disc...

Page 246: ...es will not greatly affect the image For this reason a reference is provided and occurrence of an error of a fixed amount is counted as the record of the error If the error occurs at this reference or less it is judged that the image was received successfully In this case the lines for which the error occurred are not printed and the next line is printed Note however that some facsimiles have a fu...

Page 247: ... way as RTN a fallback is made to repeat the procedure from training again and the trans mission speed is determined again to enable more reliable communica tions Fig 5 76 RTN Signal CFR TCF DCS RTN MPS RTC Calling Side transmitter Called Side receiver Message Error in received image Training Training Message ...

Page 248: ... Signal for communicating the telephone number on the receiving side to the other party Response Dial Call CED NSF CSI DIS NSS TSI DCS RTC MCF DCN EOP CFR TCF NSF CSI DIS CNG CNG Received Calling Side transmitter Called Side receiver This is an auto dial facsimile Receive in G3 mode Receive in Canon mode Telephone number is XXXXX Receive by ITU T recommendations Training Training Line check Messag...

Page 249: ...ed an HDLC structure Fig 5 78 Structure of Binary Signal NSS Transmission Reception Binary signal Signal including user name and maker code that communicates to the other party that transmission will be performed using a function other than that recommended by ITU T functions unique to manufacturer that are not provided in DCS TSI Transmission Reception Binary signal Signal for communicating the t...

Page 250: ...k Control a method of achieving highly efficient and highly reliable transmission control proce dures A feature of HDLC is a structure that checks for transmission errors in the transmitted data itself HDLC is stipulated by ISO standards as one transmission control procedure and is also used in exchanging ISDN packets The structure of HDLC is called a frame because the informa tion is prefixed and...

Page 251: ... Format In case of final frame 11001000 C8H In case of non final frame 11000000 C0H Remarks FCF Facsimile control field Shows the type of binary signal and the name of the binary signal used for the frame Format Refer to Table 5 14 8 bit or 16 bit Remarks 16 bits of FCF1 and FCF2 are used in ECM FIF Facsimile information field This indicates the details of facsimile capabilities that FCF cannot co...

Page 252: ...e transmission control signals The control field C is used for identifying the final frame at this time Fig 5 81 Example of G3 Transmission Control Signal FCS F A C FCF F DIS F A C FCF CFR FCS F F A C FCF DIS NSF CSI FCS F FIF facsimile information field Frame not having information field Preamble Frame having information field Preamble Preamble FIF facsimile information field Multiple binary sign...

Page 253: ...S X1000001 Pre message responses CFR X0100001 FTT X0100010 Post message Commands EOM X1110001 FIF does not fol low MPS X1110010 EOP X1110100 Post message responses MCF X0110001 RTP X0110011 RTN X0110010 Others DCN X1011111 Note According to the ITU T recommendation The side that receives DIS first X 1 the other side X 0 that is In regular communications the calling side X 1 the called side X 0 In ...

Page 254: ... 5 G1 G2 functions 00000000 6 V 8 function 7 0 256 octet priority 1 64 octet priority 8 Pending 9 Has G3 transmission functions polling standby 10 Has G3 reception functions 1 11 12 13 14 Image transmission speed 0000 V 27ter fallback mode 0100 V 27ter 4800bps 2400bps 1000 V 29 9600bps 7200bps 1100 V 27ter V 29 1101 V 27ter V 29 V 17 14400bps 12000bps 9600bps 7200bps other Not used or reserved 15 ...

Page 255: ...IF is extended by 8 bits after this bit 0 FIF is up to this bit 33 Field disabling capability 0 Not provided 1 Provided 34 Multiple selection polling capability 0 Not provided 1 Provided 35 PSA capability 0 Not provided 1 Provided 36 T 43 coding 0 Not provided 1 Provided 37 Plain interleaving 0 Not provided 1 Provided 38 Pending 39 Pending 40 Extension field 1 FIF is extended by 8 bits after this ...

Page 256: ...g 64 Extension field 1 FIF is extended by 8 bits after this bit 0 FIF is up to this bit 65 Processable mode 26 T 505 0 Not provided 1 Provided 66 Digital network capability 0 Not provided 1 Provided 67 Full duplex and half duplex operation 0 For half duplex operation only 1 Full duplex and half duplex operation 68 JPEG coding 0 Not provided 1 Provided 69 Full color mode 0 Not provided 1 Provided 7...

Page 257: ...ded 1 Provided 85 Substitute cipher No 2 capability 0 Not provided 1 Provided 86 Substitute cipher No 3 capability 0 Not provided 1 Provided 87 HFX40 I hashing capability 0 Not provided 1 Provided 88 Extension field 1 FIF is extended by 8 bits after this bit 0 FIF is up to this bit 89 Substitute hashing system No 2 capability 0 Not provided 1 Provided 90 Substitute hashing system No 3 capability 0...

Page 258: ...ity 0 Standard 1 Fine 16 Coding scheme 0 MH 1 MR 17 18 Document width 00 A4 10 B4 01 A3 11 Disabled 19 20 Document length 00 A4 10 B4 01 No limit to document length 11 Disabled 21 22 23 Minimum transmission time 000 20ms 100 5ms 001 40ms 111 0ms 010 10ms Others Disabled 24 Extension field 1 FIF is extended by 8 bits after this bit 0 FIF is up to this bit 25 0 26 Uncompressed mode 0 Not provided 1 ...

Page 259: ...after this bit 0 FIF is up to this bit 49 Sub address transmission selection 0 Selected 1 Not selected 50 Transmitter ID transmission selection 0 Selected 1 Not selected 51 0 52 Pending 53 Binary file transmission BFT selection 0 Selected 1 Not selected 54 Document transmission mode DTM 0 Selected 1 Not selected 55 Electronic data exchange EDI 0 Selected 1 Not selected 56 Extension field 1 FIF is ...

Page 260: ...orth American legal 215 9 355 6 mm capability 0 Not provided 1 Provided 78 Single layer sequential coding recommendation T 85 basic capability selection 0 Selected 1 Not selected 79 Single layer sequential coding recommendation T 85 optional L0 selection 0 Selected 1 Not selected 80 Extension field 1 FIF is extended by 8 bits after this bit 0 FIF is up to this bit 81 HKM key management selection 0...

Page 261: ...f FIF as indicated in Fig 5 82 LSB becomes the start within the same digit 91 Pending for security in the future 92 Pending 93 Pending 94 Pending 95 Pending 96 Extension field 1 FIF is extended by 8 bits after this bit 0 FIF is up to this bit Table 5 16 FIF of DCS Bit No Meaning Function Table 5 17 ASCII Codes Used for FIF of CSI CIG and TSI Numbers and Space Binary Codes Hexadecimal Codes MSB LSB...

Page 262: ...ufacturer in modes other than the ITU T recommendation The figure below shows the structure of the FIF for NSF NSC and NSS Fig 5 83 Structure of FIF of NSF NSC and NSS 20 F A C FCF FIF FCS F 9 8 7 6 5 4 3 2 1 0 1 1 0 0 1 1 0 0 LSB MSB Example of telephone number 01 2345 6789 F A C FCF FIF FCS F 1st byte From 4th byte on Area used freely by each manufacturer Makers codes ITU T members codes 2nd byt...

Page 263: ...d 3 On the receiving side the reverse computation to that in 1 is exe cuted from the address field to the FCS during frame reception 4 If the result is equal to a certain value it can be known that the frame is free of transmission errors This kind of transmission error detection method is called the Cyclic Redundancy Check CRC Table 5 18 Content of FIF of NSF NSC and NSS Byte Content 1st and 2nd ...

Page 264: ...tion procedure Then it outputs the polling signal NSC Calling side Called side Binary signal Signal for communicating functions other than ITU T recommendations function unique to manufacturer not contained in DIS and the maker code for requesting the other party to transmit the document option Calling Side receiver Called Side transmitter Start key is pressed to hear CED Line disconnected Line di...

Page 265: ...ved successfully On facsimiles that do not support ECM communications an error occurs on each single line when an error occurs during communications of the image signal and the line is omitted Though error control has been per formed to correct this shortcoming ECM was appended as a G3 standard optional function in 1987 as an additional recommendation to ITU T T 30 and T 4 6 10 1 Error re transmis...

Page 266: ...rify ing the continuity of the frame and the CRC check The receiving side then performs a re transmit request for error frames by PPR After the transmit ting side receives the re transmit request it transmits only the error frame as the re transmit block When the receiving side receives the re transmit block it checks for errors again by each individual frame and returns the result by PPR When blo...

Page 267: ...Side receiver Training Transmission of 1st block error not generated End of transmission of block Next block present Transmission of 2nd block error generated Training Training Frame 0 Frame 1 Frame 2 Frame 255 End of transmission of block Next block absent Re transmit of 2nd block Frame 1 Frame 2 Line disconnected Line disconnected Call Response Received successfully Error generated Error generat...

Page 268: ...64 kbytes However the final frame is sometimes a block that contains less than 256 frames In cases where the final frame is 256 bytes or less in partial pages of less than 256 frames 0 s are inserted in the section following RTC RCP The end of each block is appended with the RCP frame The end of partial pages midway during single pages and the end of frames to be re transmit are also appended with...

Page 269: ...56 frames frames are assigned a frame number within the range 0 to 255 The transmitting side is informed of the recep tion state of the 256 frames by PPR 1 is set to error frames or frames that were not received for notifying the transmitting side If the number of frames in the final block is 256 or less 1 is set to non existent frames Fig 5 86 Details of PPR 0 1 2 3 254 255 0 1 0 1 0 0 1 is set f...

Page 270: ...e transmit the same block at a lower transmission speed the rate error rate by which Fig 5 87 CTC and CTR I understand Calling Side transmitter Called Side receiver 1st transmit of 1st block Frame 0 Frame 1 Frame 255 Frame Frame Frame Frame Frame Frame 1st re transmit of 1st block 2nd re transmit of 1st block Error present Error present Error present 3rd re transmit of 1st block Frame Frame Frame ...

Page 271: ...ved When the transmitter receives ERR DCN is output to disconnect the telephone line as fallback beyond the current image trans mission speed is impossible Fig 5 88 EOR and ERR PPR PPS NULL ERR EOR DCN 2400bps PPR PPS NULL 2400bps PPR PPS NULL 2400bps PPR PPS NULL 2400bps Calling Side transmitter Called Side receiver Block transmission Frame 0 Frame 1 Frame 255 Frame Frame Frame Error present Erro...

Page 272: ...that the receiver is busy When the receiver no longer is busy due to end of printing for example MCF is output to com municate that the next block can be received The transmission times of RNR and RR are determined by timer T5 On facsimiles having a small page buffer instances where 753 758 and 783 errors frequently occur can be remedied by lengthening the timer T5 setting Fig 5 89 RNR and RR Call...

Page 273: ...ntification CI 6 9 3 4 Line Signal Monitor 6 10 3 5 Dial Control 6 11 3 6 2 wire 4 wire Conversion 6 12 3 7 Protective Circuits 6 12 3 8 Telephone Connection Control 6 14 3 9 Relay Operations 6 17 4 OPCNT BOARD 6 18 4 1 Detection of Button Input 6 18 4 2 LED Lighting Control 6 21 4 3 Display Indication Control 6 21 5 FLOW OF IMAGE SIGNALS 6 22 5 1 Transmission 6 22 5 2 Reception 6 23 6 POWER SUPPL...

Page 274: ...ly for household use G4CNT board that controls the G4 facsimile communications system Generally these printed circuit boards are connected mainly to the SCNT board In addition to these printed circuit boards there are also the PCNT board and driver board The PCNT board supplies high voltage for driving LBP printers and the driver board groups together the driver ICs for driving the various motors ...

Page 275: ...clock RTC and other components A cod ing decoding IC CODEC IC is sometimes used on some facsimile mod els Each of the ICs in the system control section is connected by a bus excluding the RTC The MPU has a built in DMA controller for increasing the efficiency of the CPU The DMA controller performs DMA transfer between each of the ICs that require transfer of large amounts of data for example betwe...

Page 276: ...connected to the system control sec tion via a bus After the document has been read by the contact sensor the resulting image data undergoes A D conversion by the image processor IC in the reading control section and image processing such as resolution conver sion in the horizontal scanning direction and the resulting image data is sent to the system controller in the system control section 2 4 Pr...

Page 277: ...ine to transfer them to the MODEM on the SCNT board and to switch the line between the fac simile and telephone Fig 6 3 Location of NCU Board The main functions of the NCU board are as follows Off hook detection Formation of DC loop Detection of calling identification CI Line signal monitor Dial control 2 wire 4 wire conversion Protective circuits Telephone connection control L1 L2 T22 T21 T12 T11...

Page 278: ...t flows between the facsimile and the exchange when the telephone becomes off hook or when the CML relay turns ON This current flow is called formation of DC loop By formation of this DC loop the exchange recognizes the response from the telephone reception terminal and performs connection of the tele phone line to enable communications For this reason the DC loop must be retained during facsimile...

Page 279: ... of DC Loop on Telephone Side When the facsimile side is set to receive automatically the CML relay turns ON when the calling identification CI is detected and the DC loop is formed between the DC seize RET circuit and the exchange B T1 T2 L1 L2 HS On hook Off hook detection circuit H relay Exchange CML relay DC seiz circuit To 2 wire 4 wire conversion circuit NCU board Off hook ON Off hook detect...

Page 280: ...SIMILE SYSTEM 6 8 Fig 6 7 Formation of DC Loop on Facsimile Side B T1 T2 L1 HS L2 Off hook detection circuit H relay Exchange ON CML relay DC seize circuit To 2 wire 4 wire conversion circuit NCU board ON ...

Page 281: ...ent The DC component of the CI arriving from the telephone line is cut by a capacitor C1 The signal is then half rectified by two photocouplers PC1 and PC2 respectively and the waveform is shaped by IC1 and IC2 The waveforms of each of these outputs CI1 and CI2 are aligned by OR cir cuit IC3 and the resulting waveform is sent to the system controller on the SCNT board as CIOR together with CI1 and...

Page 282: ...he CML relay and the H relay for monitoring the signals CNG or DTMF that arrive from the telephone line In the answering machine connection mode the signals are monitored to enable facsimile communications immediately when the other party is a facsimile The line signal monitor circuit is divided into a primary side and secondary side with a transformer provided as the boundary in the same way on t...

Page 283: ...the DC loop is formed by the P relay The dial pulse is generated by turning this relay ON and OFF If the S relay remains ON while the dial pulse is being generated the pulse waveform is influ enced by the DC seize circuit that is located after the S relay and changes as follows Fig 6 11 Waveform of Weak Pulse The waveform changes as follows when the S relay is turned OFF to indi cate that it has b...

Page 284: ...e primary side and between L1 L2 and the frame ground FG Though arrestors normally do not allow current to pass when a high voltage is applied they allow current to pass for the amount that the rated voltage is exceeded to lower the voltage across L1 and L2 and across L1 L2 and FG The arrestor lowers the voltage to the rated volt age by converting electrical energy to optical energy In some countr...

Page 285: ...mally do not allow current to pass they turn the CML relay ON when a high voltage CI arrives from the telephone line and so the current is allowed to escape to the line to protect the circuit elements from voltage rise Fig 6 15 Overcurrent Protection varistor ON ON CML relay Varistor P relay DC seize circuit L1 L2 S relay ...

Page 286: ...board There are two control patterns as described below for the functions set by these switches Prioritized connection The connection relationship between the handset and the extension tele phone is prioritized and priority is given to the handset When this setting is made the extension telephone can no longer be used when the handset is in use or is not connected The extension telephone can be us...

Page 287: ... Extension telephone cannot be used Handset in use Handset not in use on hook Hello Who s that calling Handset off hook Hello Who s that calling When the handset is made off hook Hello Who s that calling Exchange Exchange Exchange Extension telephone can be used Extension telephone cannot be used ...

Page 288: ...lel connection The relationship between the handset and the extension telephone is not prioritized allowing a three way conference call Fig 6 17 Non prioritized Connection Hello Who s that calling Hello Who s that calling Hello Who s that calling Exchange ...

Page 289: ...ate on the telephone handset or extension telephone during facsimile communications As the CML relay switches to the facsimile side during facsimile communica tions the voltage is not supplied to the off hook detection circuit When the H relay switches to the voltage terminal for off hook detection voltage is supplied to the off hook detection circuit to enable detection of the off hook state of t...

Page 290: ... MPU The following are the main functions of the OPCNT board Detection of button input LED lighting control Display indication control 4 1 Detection of Button Input The OPCNT board detects pressing of the buttons on the operation panel and relays this to the SCNT board Many buttons are provided on the top surface of the operation panel If one switch were used for one button many input ports would ...

Page 291: ...outputs Inputs KIN0 to KIN7 are pulled up internally by the OPCNT control IC to be High at all times Fig 6 20 Button Detection Timing Chart 1 When the KOUT0 to KOUT7 rows become Low one of the KIN0 to KIN7 lines becomes Low when a button is held down and the OPCNT control IC detects which button was pressed KOUT7 KOUT0 0 1 2 3 4 5 6 7 8 KIN7 KIN0 7 6 5 4 3 2 1 0 8 OPCNT control IC OPCNT control IC...

Page 292: ...put that information is relayed to the MPU by serial communications and the command that instructs whether to perform LCD display or light the LEDs is returned from the MPU according to the button that was pressed Fig 6 22 Flow of Data H L H L H L H L OPCNT control IC Divided clock Button 23 is pressed KOUT7 KOUT0 0 1 2 3 4 5 6 7 8 8 KIN7 KIN0 7 6 5 4 3 2 1 0 5V KOUT0 KOUT1 KOUT2 KIN3 Button 3 is ...

Page 293: ...Once an LED has lit the lit state of the LED continues until the lighting OFF signal arrives from the MPU Fig 6 23 LED Lighting Control 4 3 Display Indication Control When LCD code data arrives from the MPU this data is sent to the LCD module via the OPCNT control IC The character generator CG of the LCD module converts the LCD code data to data for LCD display data that indicates which pixel is t...

Page 294: ... codes the digital image data in DRAM by the CODEC and writes the resulting data to DRAM again 4 In the memory transmission mode the coded digital image data is con verted to raw data on the MPU After this coding according to the transmission mode is performed and the resulting data is written to buffer area in DRAM In the direct transmission mode the MPU codes the raw data in DRAM matched to the ...

Page 295: ...orms coding for storing the data in DRAM and writes the data to DRAM again 4 The MPU decodes the data in DRAM to raw data and sends the data to the system controller 5 As the received raw data is the data for the facsimile the system con troller performs resolution conversion on the data to obtain data for printing and sends the resulting data to the printer control section 6 At the printer contro...

Page 296: ... supply efficiency and generates little heat The following describes what sort of power supply a switching regulator is as switching regulators are used on almost all facsimiles 6 1 Switching Regulator Switching regulators supply only voltage that has dropped due to the load and turn semiconductor switches ON and OFF switching to control the supply voltage for maintaining a constant voltage This i...

Page 297: ...shows a function block diagram of a switching reg ulator Let s describes the functions of each block The AC input side is called the primary side and the DC output side the secondary side with a transformer provided as the boundary Fig 6 25 Function Block Diagram Low duty ratio OFF ON OFF ON OFF ON OFF ON ON High duty ratio Cycle Cycle Cycle Cycle Cycle Primary side Secondary side AC input DC outp...

Page 298: ... provided with a varistor When a voltage exceeding the rated voltage of the varistor is applied to the power supply line the varistor causes a current to flow to prevent voltage of and above the rated voltage from being applied A phototransistor and photocoupler are also provided extending across the primary and secondary sides for detecting abnormal output voltage When the photocoupler on the sec...

Page 299: ...1 3 Rectifying circuit The AC input signal is full wave rectified by a diode bridge to convert the AC input to DC The rectified voltage is made to have a shape like that of a mountain range and is different from the constant voltage that is output from batteries This kind of voltage is called a pulse wave Fig 6 28 Rectifier circuit Output Input power supply line side AC input waveform Full wave re...

Page 300: ...estroyed when surge current flows When the power is turned ON the thermistor s resistance value is increased to limit surge current After this current flow causes the ther mistor to self heat which in turn lowers the resistance value making it easier for current to flow When the power is turned back ON immediately after it is turned OFF the thermistor s temperature has not sufficiently fallen So c...

Page 301: ...When it is lower the diode goes out This lighting ON OFF information is relayed to the feedback port FB of the oscillation control circuit IC1 on the pri mary side via the phototransistor of PC1 The oscillation control circuit outputs the transistor ON OFF signal from the OUT port based upon this lighting ON OFF information to control the input voltage to the trans former so that the output voltag...

Page 302: ...ig 6 33 shows the smoothing circuit This circuit uses a capacitor to complement the no voltage component of the output in the above figure When there is voltage the capacitor is charged and when there is a no voltage component the capacitor discharges to supply the voltage By this action the smoothing circuit is able to smooth pulsating voltage that is output from the rectifying circuit to a DC co...

Page 303: ...y Unit on a Facsimile The power supply unit on a facsimile broadly speaking supplies voltage to two or three power lines such as those below from the AC power for household use 5V for IC drive 12V for operation panel and motor drive 24V for contact sensor and printer drive ...

Page 304: ...as a CPU V821 for controlling the entire G4CNT and a slave CPU V853 The slave CPU performs coding MR MMR or JBIG on the MR data stored in DRAM matched to the functions of the machine at the other party and during reception codes the coded data from the other party to MR data for storing on DRAM ISDN interface As its name implies this interfaces the facsimile with the ISDN line and performs outgoin...

Page 305: ... 4 5 6 ït çi FACSIMILE SYSTEM Fig 6 34 System Block Diagram of G4CNT Board CPU V821 ROM RAM SW Modem Codec Codec SLIC SW ISDN interface B1 B2 Slave CPU V853 V853 Dual port RAM HDLC controller To analog telephone ...

Page 306: ...6 34 Notes ...

Page 307: ...CES MINIFAX JAPAN ONLY A 10 3 1 F NET A 12 3 2 Minifax I MF I A 16 3 3 Minifax II MF II A 17 4 TELEPHONE LINE BAND SIGNAL SPECTRUM A 19 5 S N A 20 6 POLARITY INVERSION ON EXCHANGE A 21 7 FACTORS WHICH CAUSE DETERIORATION IN QUALITY OF FACSIMILE TRANSMISSION A 22 7 1 Usual Factors A 22 7 2 Unusual Factors A 27 7 3 Echo A 28 8 RATIO dB dBm dBV A 35 9 BINARY SIGNALS TABLE A 39 10 MAKER CODES TABLE A ...

Page 308: ...twork Fig A 2 Organization and Transmission Lines of an International Telephone Network Toll line Local line 2 wire cable system Regional Center RC District Center DC Toll Center TC End Office EO Subscriber telephone 4 wire coaxial cable system optical fiber cable system or microwave radio relay system 2 wire cable system or 4 wire coaxial cable system International exchange Domestic telephone net...

Page 309: ...radio relay system This system uses microwave radio in the 1 to 10 GHz band for transmis sion FDM DM is used as the modulation method Satellite communication system This system refers communications via communications satellites Submarine coaxial cable system This system refers to the coaxial cable that is load on the ocean floor The TASI Time Assignment Speech Interpolation system is used for eff...

Page 310: ...turalness of the voice will be slightly lost However the content infor mation of the telephone conversation can be satisfactorily transmitted For this reason telephone lines are designed for voice transmission in a frequency bandwidth of 300 to 3400 Hz Fig A 4 Ideal Frequency Characteristics of a Telephone Lines Telephone line frequency band Frequency Hz 40 30 20 10 0 2000 4000 6000 8000 10000 120...

Page 311: ...ing to the material and length of the cable Moreover transmission loss may increase 2 Full duplex communication system 4 wire cable system Same trouble as for a 2 wire cable system may occur Microwave radio relay system The S N may be affected by the weather Satellite communication system Echo approx 0 6 to 1 0 sec including return is generated The S N may change due to the effect of the solar win...

Page 312: ...s of Telephone Line Deterioration There are two main factors that cause the quality of facsimile transmis sions via telephone lines to deteriorate usual factors which always present unusual factors which suddenly occurs international communi cations and lightning The following describes typical factors For details see this chapter 7 Factors Which Cause Deterioration in Quality of Facsimile Transmi...

Page 313: ...nomenon Noise Distortion Telephone Exchange Telephone Table A 1 Phenomenon Caused by Deteriorating Factors and Countermeasures Deteriorating Factor Phenomenon Countermeasure Transmission loss An increase in transmission loss drops the signal level on the receiv ing facsimile Transmission quality drops by deterioration of S N Improve the S N ratio Increase the transmission level on the ATT switch o...

Page 314: ...of the SSSW Slow down the transmission speed Phase jitter Lines may be missed if jitter is sig nificant Improve the S N ratio Increase the transmission level on the ATT switch of the SSSW Slow down the transmission speed Impulse noise The same phenomenon as white noise and level variation occur Improve the S N ratio Increase the transmission level on the ATT switch of the SSSW Slow down the transm...

Page 315: ...g it may not be possible to connect Insert a pause in the registered tele phone number Lightning High voltage is conducted on tele phone lines when lightning strikes This voltage passes through the NCU board and may damage the inside of the facsimile Take high quality ground Unplug the power supply cord and telephone line during thunder storms Table A 1 Phenomenon Caused by Deteriorating Factors a...

Page 316: ... NTT Nippon Telephone and Telegraph views terminals and networks as an integrated system and is offering Facsimile communi cation network services F NET as a network service and Minifax I MF I and Minifax II MF II as terminal services to satisfy the above user s needs and increase overall performance including communications costs Fig A 6 F NET and Minifax When you subscribe to a F NET normally yo...

Page 317: ...A 11 1 2 3 4 5 6 A çi Fig A 7 F NET and PSTN PSTN MF MF MF Subscriber exchange F NET Subscriber exchange Subscriber exchange ...

Page 318: ...mes of data 4 Reasonable communications costs can be achieved by sharing existing subscriber telephone network facilities Fig A 8 Configuration of F NET STOC TS FX TS FX TS LS FCAP LCE FCAP SIE STOC TS FX TS LS FCAP LCE FCAP SIE FAX FAX PSTN TS FX TS FX Tandem trunk electronic exchange having facsimile communications functions TS Tandem trunk exchange LS Subscriber exchange STOC Storage and conver...

Page 319: ...ading section of image signals with caller number before transmitting the image signals to the facsimile terminal Monitors the digital transmission line between the STOC and TS FX 3 Tandem trunk electronic exchange TS FX having facsimile com munications functions Switches and connects between the LS or TS and FCAP Holds the subscriber data and performs transmitter verification charging and recordi...

Page 320: ... on F NET Fig A 9 Connection Procedure Example of communications outside area Calling FCAP LCE Calling FCAP SIE Calling TS FX Calling STOC Calling LS Called LS Called FCAP SIE Called FCAP LCE Called STOC Called TS FX Control signal network 1 161 Caller number 2 Called party number calling party number etc 3 Subscriber file verification 4 Transmit instruction 5 Image signal 9 Storage and conversion...

Page 321: ...lexes the received image signals and transmits them by high speed digital transmission to the calling STOC 7 The calling STOC stores the image signals to memory If the docu ment size must be converted it stores the image signals to memory after performing conversion 8 The calling STOC looks for free space on the digital transmission line and transmits the calling party number called party number a...

Page 322: ...ons operations 3 2 Minifax I MF I Minifax I originally is the name of Class 1 connection arrangement ter minals for F NET The transmission method used on these terminals is also called Minifax I MF I Any simple mention of Minifax refers to Mini fax I Recent Canon facsimiles do not support communications with Minifax I ...

Page 323: ...shows the procedure for transmitting to F NET from a fac simile terminal Fig A 10 Control Procedure of F NET Compatible G3 Facsimile terminal to F NET 2100Hz Offhook Dial 161 DIS TSI DCS TRAINING TCF TRAINING CFR MESSAGE RTC Q MCF DCN When Q is MPS When Q is EOM CSI 1 1 Q indicates one of the EOM MPS or EOP signals F NET FCAP Dial tone Continuous 400 Hz signal Facsimile network selection signal 2n...

Page 324: ... 11 Control Procedure of F NET Compatible G3 F NET to facsimile terminal F NET FCAP FAX alert signal Detection of FAX alert signal Line disconnection 1300 Hz 2 2 10sec CED NSF CSI DIS TSI DCS TRAINING TCF TRAINING CFR MESSAGE RTC Q MCF DCN When Q is MPS When Q is EOM 2100 Hz 2 6 4sec ...

Page 325: ...st cables Fig A 12 Telephone Line Bandwidth and Signal Spectrum 1850 1650 0 300 1000 2000 3000 3400 1100 1300 CNG FC Japan only 1800 1700 2100 CED Telephone line frequency characteristics Transmittance dB Frequency Hz Frequency Hz Frequency Hz Frequency Hz Tonal signals Signal level dBm Signal level dBm Signal level dBm G3 procedure signals binary signals FSK G3 image signals 4800 2400bps PSK G3 i...

Page 326: ... above condition is reversed It can be said that the performance of the receiving facsimile is high if it can receive image signals at a small S N If signals can be received prop erly from large noise this is a clear indication that performance is high The Fig A 15 shows the relationship between the signal level and noise level Fig A 15 Relationship between Signal Level and Noise Level Measured wa...

Page 327: ...ification Sends the ringing back tone to the calling party Restores original polarity after response from called party Deactivates the calling identification Inverts the polarity on the calling party and deactivates the ringing back tone Telephone State Operation of Exchange Telephone Line State Both onhook normal state Monitors states of terminals Calling party offhook loop closed Exchange is sta...

Page 328: ... A 17 Example of Loss Distribution on a Toll Line Loaded Line In the past when there were no suitable amplifiers excessive attenuation prevented telephone conversations from being conducted when long dis tance calls were made However as you can tell from the Fig A 18 the amount of attenuation is reduced by self induction action if coils are inserted in the line at fixed intervals These coils are c...

Page 329: ...wever in the case of G3 facsimile transmission image signals can no longer be received properly and errors occur frequently if the distortion is significant Fig A 20 Attenuation Characteristics between EOs Fig A 18 Loading cable Fig A 19 Attenuation Characteristics of Non loading Cable L L L L L L S S S Approx 1km 0 1 2 3 4 5 4 3 2 1 NL Non loading Attenuation dB L Loading Frequency kHz 15 10 5 0 ...

Page 330: ...m if the delay is inconsis tent within the required frequency band This is called group delay distor tion Group delay distortion occurs due to multiplexing that is performed at exchange in the telephone hierarchy at or above the EO stage Group delay distortion does not cause any problems during telephone con versations as the sensitivity of the human ear is not so sharp However in G3 facsimile tra...

Page 331: ...ion is used in FDM the carrier wave fc1 is not transmitted from the transmitter to the receiver Instead the receiver uses its own carrier fc2 to regenerate the signal Generally a slight frequency difference f between fc1 and fc2 The Fig A 23 shows its generation procedure Frequency offset does not cause any special problems in telephone conver sations In G3 facsimile transmission however waveforms...

Page 332: ...cy axis There is another multiplex method TDM Time Division Multiplex in which one transmission line is used alternately for time sharing 8 Phase jitter Phase jitter presents the fluctuation of the signal phase Phase jitter occurs when the signal is modulated with phase modulation PM or fre quency modulation FM by some cause Phase jitter does not cause any special problems in telephone conversa ti...

Page 333: ...Step Exchange 2 Short breaks A short break is a sudden drop in the reception signal level of 6 dB or more for 1 msec to 60 sec continuous Short breaks are caused by fading in microwave radio ralay and satellite communications system zones or by faulty contacts on equipment and cables Short breaks do not cause any special problems in telephone conversations as long as the break is not continuous Ho...

Page 334: ...ter istics impedance and in hybrid circuits see figure Fig A 29 for details of a 2 wire 4 wire conversion circuit It is very difficult to eliminate this reflection This difference in characteristic impedances is sometimes called impedance mismatching Fig A 27 Reflection of Signal Energy Communication satellites and submarine cables are used as the transmis sion lines in international communication...

Page 335: ...ne lines and domestic long distance transmission lines where delay exceeds 45 msec Echo suppressors are equipped with special switches for eliminating voice signals that are reflected on the other party while the speaker is still talking Each suppressors are equipped on each channel The Fig A 29 shows the operation of switches when the voice of the speaker on the right reaches the other party on t...

Page 336: ...hat lasts for 300 100msec or longer so that echo occurs The echo suppressor is turned back on when a no signal state lasts for 100 msec or more The CED that appears at the start of the facsimile procedure disables the echo suppressor functions as its frequency is 2100 Hz This causes echo to occur as shown in the Fig A 30 Since this causes an inconvenience in fac simile transmission adopt counterme...

Page 337: ...h unimpaired thus allowing full duplex transmission Though the performance of echo cancellers is superior to that of echo sup pressors echo cancellers are more complex and expensive The percentage of equipment on which echo cancellers are equipped is increasing Cur rently echo cancellers are equipped on 100 of equipment in the USA and Japan Fig A 31 Echo Canceller Return Loss Return loss is a rati...

Page 338: ...er Add a tonal signal 1080 Hz 0 5 sec before the CED tone selected by the SSSW By adding a tone other than 2100 21 Hz before CED disabling of the echo suppressor can be prevented A tone of 1080 Hz is added on Canon facsimiles Fig A 33 Echo Countermeasure on Receiver TX RX CED Preamble NSF CSI DIS Tonal signal 1080 Hz 0 5 sec Long distance transmission line ...

Page 339: ...c This function is provided on all Canon facsimi les After transmitting each binary signal ignore binary signals from the other party for 0 6 to 0 7 sec differs according to model of facsimile as shown in the Fig A 35 This is because the regular echo delay is within 0 6 sec By performing this process the facsimile is not likely to be deceived by its own signals Moreover since the preamble time is ...

Page 340: ... on Both Transmitter and Receiver TX RX CED Preamble DIS DCS Preamble Preamble Preamble Preamble Preamble Training TCF Training MESSAGE RTC CFR EOP DCN MCF 0 6 0 7sec Long distance transmission line 0 6 0 7sec 0 6 0 7sec 0 6 0 7sec ...

Page 341: ...s as follows The same applies to the current ratio When these ratios of power voltage and current are greater than 1 the dB value is a positive value When they are smaller the dB value is a negative value So a positive dB value expresses gain while a nagative dB value expresses attenuation Practical dB values The following advantages are obtained from the logarithmic characteris tics Po times Pi 1...

Page 342: ... attenuation can be calculated by simply adding each gain and each attenuation respec tively 2 dBm dB described above is based upon the power ratio between the input termi nal and the output terminal In effect this is a relative indication Absolute indication can be achieved provided that the reference for com parison is fixed to a certain value Generally the following is supposed Fig A 37 Assumpt...

Page 343: ...ken to 1 V If the voltage of the measurement point is taken to be E V then dBV is defined in the following equation The dBm indication of the voltage on a 600 ohm impedance system is described as Voltage 20 log10 E dBm where impedance of the measure ment point is 600 ohm 0 775V Table A 2 Conversion Table for Ratio and dB Table A 3 Conversion Table for dBm and Power Voltage on a 600 ohm Impedance S...

Page 344: ...hip between dBm indication and dBV indication That is if we added 2 2 dB to the value of the dBV indication the result is the dBm indication 20 log10 E 20 log10 E 0 775 1 20 log10 E log10 E 0 775 20 log10 E 1 20 log10 1 0 775 E 0 775 dBm dBV 2 2dB ...

Page 345: ... Message B FCF1 X111 0001 EOP End of Procedure B FCF1 X111 0100 MPS Multiple Page Signal B FCF1 X111 0010 NSS Non Standard Facilities Setup B FCF1 X100 0100 PRI EOM Procedure Interrupt End of Message B FCF1 X111 1001 PRI EOP Procedure Interrupt End of Procedure B FCF1 X111 1100 PRI MPS Procedure Interrupt Multiple Page Signal B FCF1 X111 1010 TCF Training Check 0 continuous for 1 5 seconds TSI Tra...

Page 346: ... PIN Procedure Interrupt Negative B FCF1 X011 0100 PIP Procedure Interrupt Positive B FCF1 X011 0101 RTN Retrain Negative B FCF1 X011 0010 RTP Retrain Positive B FCF1 X011 0011 SUB Subaddress B FCF1 X100 0011 PWD Password B FCF1 X100 0101 Common signals CRP Command Repeat B FCF1 X101 1000 DCN Disconnect B FCF1 X101 1111 Image signals EOL End Of Line B 0000 0000 0001 001H RTC Return To Control 6 co...

Page 347: ...CF2 1111 1100 ERR Response to End Of Retrans mission B FCF1 X011 1000 PPR Partial Page Request B FCF1 X011 1101 PPS Partial Page Signal B FCF1 X111 1101 PPS NULL FCF2 0000 0000 PPS EOM FCF2 1111 0001 PPS MPS FCF2 1111 0010 PPS EOP FCF2 1111 0100 PPS PRI EOM FCF2 1111 1001 PPS PRI MPS FCF2 1111 1010 PPS PRI EOP FCF2 1111 1100 RNR Receive Not Ready B FCF1 X011 0111 RR Receive Ready B FCF1 X111 0110 ...

Page 348: ...00 YGREC SYSTEMS 00 05 0000 0000 0000 0101 NAKAJIMA ALL 00 06 0000 0000 0000 0110 JRC 00 07 0000 0000 0000 0111 00 08 0000 0000 0000 1000 FUNAI 00 09 0000 0000 0000 1001 ALTECH 00 0A 0000 0000 0000 1010 ORION ELECTRIC 00 0B 0000 0000 0000 1011 USC 00 0C 0000 0000 0000 1100 JBS 00 0D 0000 0000 0000 1101 MINOLTA 00 0E 0000 0000 0000 1110 KYOCERA 40 0100 0000 NTT 50 0101 0000 KDD 60 0110 0000 MASTER ...

Page 349: ... PANASONIC MATSUSHITA A0 1010 0000 MITSUBISHI A2 1010 0010 MURATA A4 1010 0100 RICOH A6 1010 0110 OMRON A8 1010 1000 TOYOCOM AA 1010 1010 NITSUKO AD 1010 1101 MATSUSHITA COMMUNICATION AE 1010 1110 TEC B0 1011 0000 LOGIC SYSTEM INTER B2 1011 0010 OHKURA ELECTRIC B4 1011 0100 SONY B6 1011 0110 HITACHI TELECOM TECH B8 1011 1000 HITACHI SOFTWARE BA 1011 1010 KUONI BC 1011 1100 IBM JAPAN BE 1011 1110 S...

Page 350: ...ks A0 841 1189 A1 594 841 Size of an opened out newspaper A2 420 594 A3 297 420 A4 210 297 A5 148 210 A6 105 148 Table A 7 ISO B series Document Sizes Size mm x mm Remarks B0 1030 1456 B1 728 1030 B2 515 728 B3 364 515 B4 257 364 B5 182 257 B6 128 182 Table A 8 Standard Document Sizes Widely Used in North America Name Size inches Size mm Remarks Letter 8 11 216 279 Legal 8 14 216 356 Ledger 11 17 ...

Page 351: ...Yes Yes Yes Yes Yes No CFR Yes No No B Transmitting station Transmit CNG COMMAND REC Go to non specified procedures DIS or DTC COMPT REMOTE REC DOC TO XMIT COMPT REMOTE XMTR SET MODE Transmit TSI NSS or TSI DCS Transmit trsining TCF RESPONSE REC 3RD TRY 3RD TRY DIS or DTC REPHASE TRAIN FTT Error correction Transmit training Transmit facsmile message Transmit facsmile message Transmit training Tran...

Page 352: ...s No Yes Yes Yes No No No Yes No Yes No No No Yes Tranamit MPS PRI MPS RESPONSE REC 3RD TRY PIN or PIP Alert operator LINE REQ T3 elapsed Transmit PRI Q Phone to line OK to continue Go to beginning of phase B Transmitting station Transmit EOP PRI EOP Transmit EOM PRI EOM RESPONSE REC RESPONSE REC 3RD TRY 3RD TRY PIN or PIP CAPABLE RE XMIT CAPABLE RE XMIT Go to beginning of phase B Transmit DCN Dis...

Page 353: ...A 47 1 2 3 4 5 6 A çi Fig A 41 Transmitting Station Procedure 3 Yes No No No Yes Yes a b c d Transmitting station END OF PAGE LAST DOC Interrupt CHANGE MODE ...

Page 354: ...o No No Yes Yes No No Yes Yes Yes No No Yes No Yes Yes No PPR RNR MCF C C C C a Transmitting station Transmit PPS NULL 3RD TRY RESPONSE REC RR RESPONSE REC 4TH PPR CONTINUE TO CORRECT CTC RESPONSE REC Transmit training Transmit error frames Transmit RCP ...

Page 355: ... Yes Yes No No Yes Yes Yes No No Yes No Yes Yes No PPR RNR MCF C C C C E No Yes b Transmitting station Transmit PPS MPS PPS PRI MPS 3RD TRY RESPONSE REC RR RESPONSE REC PIP or PIN 4TH PPR CONTINUE TO CORRECT CTC RESPONSE REC Transmit training Transmit error frames Transmit RCP ...

Page 356: ... No Yes Yes Yes No No Yes No Yes No PPR RNR MCF No Yes Yes Vc C C C C C E Transmitting station Transmit PPS EOP PPS PRI EOP 3RD TRY RESPONSE REC RR RESPONSE REC PIP or PIN 4TH PPR CONTINUE TO CORRECT CTC RESPONSE REC Transmit training Transmit error frames Transmit RCP VI ...

Page 357: ...o Yes Yes Yes No No Yes No Yes Yes No PPR RNR MCF No Yes d C C C C E Transmitting station Transmit PPS EOM PPS PRI EOM 3RD TRY RESPONSE REC RR RESPONSE REC Go to beginning of phase B PIP or PIN 4TH PPR CTC RESPONSE REC CONTINUE TO CORRECT Transmit training Transmit error frames Transmit RCP ...

Page 358: ...A 52 Fig A 46 Transmitting Station Procedure 8 No No Yes Yes No Yes d b a c Transmitting station END OF PAGE LAST DOC CHANGE MODE ...

Page 359: ... 3 4 5 6 A çi Fig A 47 Transmitting Station Procedure 9 No No Yes Yes Yes No Yes No No Yes Yes RNR ERR No a C C C C Transmitting station Transmit EOR NULL 3RD TRY RESPONSE REC CONT WITH NEXT MSG RR RESPONSE REC ...

Page 360: ...Transmitting Station Procedure 10 Yes No No Yes No Yes No Yes No No Yes Yes RNR ERR Yes No Yes PIN b C C C C E Transmitting station Transmit EOR MPS EOR PRI MPS RESPONSE REC RR RESPONSE REC CONT WITH NEXT MSG 3RD TRY ...

Page 361: ... 3 4 5 6 A çi Fig A 49 Transmitting Station Procedure 11 Yes No C Yes No RNR No Yes ERR No PIN No C No Yes E C C Yes Yes c Transmitting station Transmit EOR EOP EOR PRI EOP 3RD TRY RESPONSE REC RR RESPONSE REC ...

Page 362: ...Station Procedure 12 VId Yes No C Yes No RNR No Yes ERR No PIN No C No Yes E C C Yes Yes Yes No CONT WITH NEXT MSG Go to beginning of phase B Transmitting station Transmit EOR EOM EOR PRI EOM 3RD TRY RR RESPONSE REC RESPONSE REC ...

Page 363: ...Yes No No Yes No Yes EOM Yes Yes Yes Yes No A F RESPONSE REC Receiving station Transmit NSF CSI DIS NSC CIG DTC 3RD TRY T1 elapsed Go to non specified procedures MSG CARRIER REC LOCAL INT Receive phasing training TCF Phase TCF OK Respond CFR Respond FTT Error correction COMMAND REC T2 elapsed Error correction 3RD TRY Receiver training Receive facsmile message MSG CARRIER REC ...

Page 364: ...s No No Yes Yes Yes No No Yes F No F No Yes Receiving station LINE REQ 3RD PRI Q Transmit PIN or PIP Phone to line OK to continue Go to beginning of phase B LOCAL INT COPY QUALITY OK REPHASE TRAIN Respond MCF Respond RTP Disconnect the line Alert operator Respond RTN Transmit PIN Transmit PIP COPY QUALITY OK ...

Page 365: ... Station Procedure 3 CTC No Yes B F PRI Q Yes No a b No Yes Yes B Yes No No Receiving station Respond CTR Transmit PIP Transmit PIN Transmit PIN or PIP Phone to line OK to continue Go to beginning of phase B ALERT OPERATOR LINE REQ T3 elapsed ...

Page 366: ...s Yes No a Yes Yes No Yes No No F No Yes F No No Yes Yes a F Yes F Yes No No Receiving station COPY QUALITY OK RECEIVE READY Respond RNR COMMAND REC T2 elapsed RR or PPS Q Respond PPR ALERT OPERATOR LINE REQ 3RD PPS PRI Q COPY QUALITY OK END OF PAGE LOCAL INT Transmit PIP Respond MCF ...

Page 367: ...EOR Q No Yes EOR PRI Q Yes No Yes Yes B No B Yes Yes No F a No No No Yes Yes Yes No b F F No No Yes Receiving station RECEIVE READY Respond RNR COMMAND REC T2 elapsed RR or EOR Q LINE REQ 3RD EOR PRI Q END OF PAGE LOCAL INT Transmit PIN Respond ERR ALERT OPERATOR ...

Page 368: ...A 62 Fig A 56 Receiving Station Procedure 6 RR No Yes B Yes No VII a a Receiving station Last post message command PPS Q ...

Page 369: ...s No No Yes Yes No No No No Yes 1 Yes Yes 2 T4 4 5s 15 manual units T4 3 0s 15 automatic units RESPONSE REC Enter T4 delayed Flag Receive a frame FCS error 3s delayed Signal gone Transmit DCN Disconnect the line 200 ms delay Return No Optional response Return Yes Process optional response Signal gone 3 second delayed 200 ms delay ...

Page 370: ... No Yes No Yes Yes Yes DCN 4 Yes No No Yes No Yes Signal gone 3s delay 200 ms delay Return No Return Yes Disconnect line CRP option 200 ms delay Signal gone 3s delay Respond CRP COMMAND REC Enter Flag Reset 6s timer T2 Receive a frame FCS error Optional command Process optional command ...

Page 371: ...A 65 1 2 3 4 5 6 A çi Fig A 59 RR Response Reception 1 Yes No 1 Yes Yes No No RR RESPONSE REC Enter T5 elapsed Transmit RR RESPONSE REC 3RD TRY Return No Return Yes ...

Page 372: ...A 66 Fig A 60 CTC Response Reception No Yes Yes CTR Yes No No CTC RESPONSE REC Enter SET MODE Transmit CTC RESPONSE REC 3RD TRY Return No Return Yes ...

Page 373: ...e created based upon these ASCII codes Bus A digital transfer path shared by multiple devices Connection of these devices on this bus is called bus connection For a bus connection ICs or other elements are sometimes connected on the circuit board or a digital terminal is sometimes con nected to an ISDN line Capillary phenomenon The phenomenon where the level of a liquid in a tube is higher or lowe...

Page 374: ...od that uses a combination of two specific frequencies like that in push button dialing Exchange The equipment for connecting lines from terminals and exchange stations Friction coefficient The ratio between the friction force parallel to a contacting surface acting on contacting parts and the force acting perpendicularly on a mutually contacting surface Gamma characteristics Gamma characteristics...

Page 375: ...mber refers to the remainder obtained by dividing that number by 2 MPU Micro Processing Unit The part that controls the core functions of a computer The MPU is divided into three parts with different functions the I O unit control unit and arithmetic logic unit ALU Non feed The document placed on the copy board is not fed Pixel The smallest element that comprises an image Pseudo bell The bell that...

Page 376: ...k circuit that counts date and time Vertical scanning Reading of documents in the vertical direc tion is called vertical scanning and the number of scanlines per unit length when the document is separated in the vertical scanning direction is called the vertical scanning density vertical resolution G3 facsimiles separate documents into 3 85 lines 7 7 lines or 15 4 lines per 1 mm so the vertical sc...

Page 377: ...ion 1 27 6 9 CIG 5 123 CJ 5 76 Claw separation method 4 13 Cleaning 4 56 CM 5 76 CML relay 6 17 CNG 5 76 5 92 Coding scheme 5 6 Color facsimile 2 23 Communications control section 6 4 Compression method 5 6 Condensing lens 4 34 Contact resistance 1 6 Contact sensor 3 10 Crossbar type 1 25 CSI 5 81 5 106 CTC 5 128 CTR 5 128 Curvature separation 4 43 Cylindrical lens 4 33 D D A conversion circuit 3 ...

Page 378: ...5 47 FTT 5 95 5 103 Full duplex communication system A 5 Full wave rectified 6 27 G G1 2 3 G2 2 3 G3 2 3 2 4 5 2 G4 2 3 2 6 G4CNT board 6 32 GENESIS 3 16 Grade 1 20 Group 2 3 H H relay 6 17 Half duplex communication system A 5 Handset 1 2 HDLC 5 108 Home position 4 53 4 55 Hook button 1 2 1 8 Horizontal scanning 5 3 Hybrid network 1 17 I Image data processing 4 3 Image signal 5 90 Incoming call 1 ...

Page 379: ...ing 5 48 Photosensitive drum 4 37 Pickup section 4 12 Polling 5 122 PPR 5 127 PPS 1 9 PPS EOM 5 126 PPS EOP 5 83 5 126 PPS MPS 5 126 PPS NULL 5 126 PPS Q 5 126 Preamble 5 90 Pre scan 3 14 Primary charging step 4 35 4 37 Printer control section 6 4 Printer engine control section 4 27 PRNT signal 4 28 PSK 5 48 PSTN 2 3 Public switched telephone network 2 3 Pumping 4 55 4 57 Purge unit 4 56 Pushbutto...

Page 380: ... band system 1 24 Toll center 1 21 Toll exchange 1 21 Toll line 1 21 Toll network 1 21 1 24 Tonal signal 5 90 Tone dial 1 11 Toner cartridge 4 46 Toner saving 4 11 TOP signal 4 28 Toric lens 4 33 Training 5 95 5 96 5 102 Transfer step 4 36 4 42 Transit exchange 1 19 Transit trunk 1 19 1 24 Transmission control procedure 5 89 Transmission speed 5 5 Transmission time 5 5 Traversal trunk 1 24 Trellis...

Page 381: ...PRINTED IN JAPAN IMPRIME AU JAPON 0400AB0 40 0 CANON INC Printied on paper that contains 60 reused paper ...

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