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US Robotics COURIER, User Manual

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Summary of Contents for COURIER

Page 1: ...COURIER HIGH SPEED MODEMS COURIER HST Dual Standard with ASL COURIER HST Dual Standard FAX with ASL COURIER V 32 bis with ASL COURIER V 32 bis FAX with ASL COURIER HST with ASLTM COURIER HST FAX with ASL USER S MANUAL ...

Page 2: ... Standard with ASL COURIER HST Dual Standard FAX with ASL COURIER V 32 bis with ASL COURIER 32 bis FAX with ASL COURIER HST with ASL COURIER HST FAX with ASL USER S MANUAL 1992 by U S Robotic Inc 8100 North McCormick Blvd Skokie IL 60076 All Rights Reserved ...

Page 3: ... Conversely if you ve purchased a Courier HST modem disregard the instructions concerning V 32 V 32 bis operations All Courier high speed modems connect automatically with remote modems operating at 14 4K 12K 9600 7200 4800 2400 1200 300 bps as long as the remote modems observe the standards listed under Compatibility in Chapter 1 Courier HST modems also connect with other Courier HST modems at 16...

Page 4: ... __ Asynchronous Calls r I I I Glossary I L 1 r 1 I Ch 8 I I Inquiries I HELP L _ _ _j App A Error Control Compression I Advanced Users Ch 3 Quick Start In Ch 4 Throughput Guidelines In App B Default Settings r I In Ch 8 I ATl6 Link I I Diagnostics L _ _ _j Dashed lines indicate optional references Additional points of reference Page Page 3 1 HST and V 32 V 32 bis Modes E 2 Fax Operations Fax mode...

Page 5: ...Adaptive Speed Leveling ASL are trademarks of U S Robotics Inc Apple is a registered trademark of Apple Computer Inc Hewlett Packard 3000 is a trademark of Hewlett Packard Company IBM PC PC XT PC AT and Systems Network Architecture SNA are trademarks of International Business Machines Corp Microcom Networking Protocol MNP is a trademark of Microcom Inc Touch Tone is a trademark of American Telepho...

Page 6: ...1 Operational Requirements 2 1 RS 232 Requirements 2 2 Switches 2 3 Front Panel Indicators 2 4 Installing the Modem 2 4 Testing the Installation 2 7 Chapter 3 Quick Start Asynchronous Calls AsynchronousI Synchronous Communication 3 1 Initial Modem Settings 3 1 Recommended Settings 3 2 Alternative Settings 3 3 Data Format 3 4 Storing Defaults in Nonvolatile Memory 3 5 Dialing 3 5 Link Rate Negotiat...

Page 7: ...n 4 14 Link Rate Select Nn 4 15 Data Set Ready Sn 4 16 Data Terminal Ready On 4 17 Carrier Detect Cn 4 18 Rack Controller Unit Access Rn 4 18 Touch Tone Recognition Tn 4 18 Chapter 5 Internal Controls Setting Using Defaults 5 1 Writing Defaults to NVRAM W 5 1 Loading the Factory Defaults F 5 2 Reset Z 5 3 Storing a Command String ZC s 5 3 Storing Telephone Numbers Zn s 5 4 Result Codes 5 4 Respons...

Page 8: ...ommand Mode 6 5 Dialing Letters 6 5 Transferring Calls 6 6 Wait for an Answer 6 6 Reversing Originate Answer Frequencies R 6 7 Dialing a Stored Number DSn 6 7 Redialing 6 7 Dial the Last Dialed Number DL 6 8 Re execute the Last Command A 6 8 Automated Redialing A 6 8 Continuous Repeat 6 9 Continuous Re Execute A 6 9 Exiting Repeat Mode 6 9 Escape Code Operations 6 9 Modem Response to 6 10 Returnin...

Page 9: ... Up 7 6 Chapter 8 Queries and Help Screens User Inquiries In 8 1 S Register Query Sr 8 6 Phone Number Query Zn 8 6 Last Dialed Number Inquiry DL 8 6 Help Screens 8 6 Stop Restart Display 8 6 Cancel Display 8 7 Basic Command Set 8 7 Extended Command Set 8 7 Dialing D 8 8 S Register Functions S 8 9 PART II REFERENCE Appendix A Link Negotiation Handshaking and Error Control Link Negotiation Handshaki...

Page 10: ... D 1 Appendix E Fax and Other Operations Fax Operations E 2 Voice Data E 3 Remote Configuration E 7 High SpeedI Low Speed Protocol E 13 Dedicated Line and Leased Line Operation E 16 Hewlett Packard 3000 Installations E 19 Ml MIC Operations E 20 Appendix F Modem Testing Testing with T F 1 Ending a Test TO S18 F 1 Analog Loopback Tl TS F 2 T2 F 4 Digital Loopback T3 F 4 T4 TS F 5 Remote Digital Loop...

Page 11: ... the exclusion or limitation of incidental or consequential damages or allow limitations on how long an implied warranty lasts so the above limitations or exclusion may not apply to you This warranty gives you specific legal rights and you may also have other rights which vary from state to state To obtain service under this warranty contact the U S Robotics Technical Support Department at 800 982...

Page 12: ...e brouillage radioelectrique edicte par le ministere des Communications du Canada CONNECTING TO THE TELEPHONE COMPANY It is not necessary to notify the telephone company before installing the modem However the telephone company may request the telephone number s to which the Courier is connected and the FCC information printed above If the telephone company has any questions or raises problems ask...

Page 13: ...dio or television reception which you can determine by monitoring reception when the modem is on and off try to correct the problem with one or more of the following measures Reorient the receiving antenna Relocate the computer with respect to the receiver Relocate the computer and or the receiver so that they are on separate branch circuits If necessary consult your dealer or an experienced radio...

Page 14: ... certified equipment should be made by an authorized Canadian maintenance facility designated by the supplier Any repairs or alterations made by a user to this equipment or equipment malfunctions may give the telecommunications company cause to request the user to disconnect the equipment For your own protection make sure that the electrical ground connections of the power utility telephone lines ...

Page 15: ... ...

Page 16: ... HST connections In addition our high speed modems monitor phone line quality and perform Adaptive Speed Leveling Like most high speed modems Courier modems fall back to the next lower speed for example 12K then 9600 if poor line conditions warrant Unlike other modems however that stay at the lower rate for the rest of the call Courier modems detect improved line conditions and shift upward again ...

Page 17: ...ave always been able to phone and make arrangements with another user before turning control of the call over to the modems A new feature a switch on the modem s front panel allows you to change from voice to data and back again without issuing a command If you don t ordinarily use voice and data in the same call you can assign the switch a different function that normally requires a command such ...

Page 18: ...r Register 516 test options are available The modem performs three loopback tests analog digital and remote digital See Appendix F for information Inactivity Timer You can set the modem to automatically hang up after a speci fied number of minutes if there is no activity on the phone line Call Duration Reporting The modem records the duration of your calls in hours minutes and seconds This feature...

Page 19: ...buffer without your having to enter the number again Automated Redialing You can put the modem into Repeat Mode to continuously redial if a previous dial attempt fails to connect This is especially use ful in dialing services whose lines are often busy Quote Mode Set the modem to Quote Mode if you want it to dial an alpha betic acronym instead of a numeric number COMPATIBILITY The Courier adheres ...

Page 20: ... TIA EIA 578 Service Class 1 Asynchronous Facsimile DCE Control Standard CCITT V 29 9600I 7200 bps CCITT V 27 ter 4800 2400 bps CCITT V 21 300 bps Other compatibility features include the following standards and certification Can be used with any computer or terminal that is com patible with the RS 232 standard interface Can be used with any computer or terminal that uses ASCII the standard charac...

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Page 22: ...ings recommended for a number of popular communications software products plus tips for a quick startup An RJl1C phone cord A power adapter A Quick Reference card in this manual Your warranty card to be filled out and returned to U S Robotics Inc OPERATIONAL REQUIREMENTS The Courier modem has minimal operational requirements Be sure to read the information in the front of this manual about radio a...

Page 23: ... transparent Others prefer a program that allows them to use the modem s AT command set sometimes and their soft ware at other times depending on the task at hand Whichever you prefer review at least the Quick Start Chapter 3 so that you have a basic understanding of the modem s requirements and operation RS 232 Requirements You ll need an RS 232 cable to connect the modem to your com puter or ter...

Page 24: ...in Appendix B The guidelines there will help you to avoid signal degradation at very high speeds SWITCHES Voice Data This pushbutton switch is used primarily to switch between voice and data communications during a call Detailed instructions are in Appendix E Voice Data Calls The switch has multiple functions however Options are as follows Disable the switch Force the modem off hook in Originate m...

Page 25: ...dem Ready Power Request to Send Clear to Send Synchronous Automatic Repeat Request Error Control I Fax Mode Fax modems only INSTALLING THE MODEM 1 Turn off the computer or terminal and its peripheral devices 2 Examine the label on the bottom of the modem In addition to the summaries and other information the label contains icons to aid in modem assembly Check the interfaces at the back of the mode...

Page 26: ...ur present phone cable from the wall jack Plug one end of the phone cable that came with the modem into the modem s phone jack that is near the wall jack icon on the bottom label Plug the other end into the wall jack NOTE Older telephone installations may not have the appropriate modular wall jack and plug Adapters and RJl1C connectors are available from your telephone com pany or computer dealer ...

Page 27: ...ll also find descriptions of switch functions and options in Appendix B If you already know your requirements use the guide on the bottom of the modem or the summary in the Quick Refer ence Card to verify the switch positions NOTE If you have built your own RS 232 cable and it does not support Data Terminal Ready DTR set DIP switch 1 ON for the DTR override The override causes the modem to operate...

Page 28: ...he CD override MR Modem Ready Power ON CS Clear to Send TR Data Terminal Ready if you have set DIP switch 1 ON enabling the DTR override For more information on the front panel indicators see Appendix B 2 Set your terminal or software to 19 2K bps or 9600 bps In addition set a word length of either 7 bits plus 1 parity bit or 8 bits with no parity it doesn t matter which now and 1 Stop bit 3 If yo...

Page 29: ...entered command is not displayed your local echo is OFF To turn the local echo ON send the modem the following command ATE1 Enter If double characters appear on the screen both your modem and software are set to local echo ON Either set your soft ware to local echo OFF or turn the modem s echo OFF with the following command ATEO Enter Troubleshooting If no OK appears on your screen review the foll...

Page 30: ... ON position Then initiate the new switch setting with the following reset command ATZ Enter 5 A final check of the modem is to see that it gets a dial tone Type the following manual Dial command ATD Enter On receipt of the command the modem goes off hook and waits for a dial tone The OH indicator lights and you ll hear the dial tone from the modem s speaker To cancel the operation press any key I...

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Page 32: ... and other large computers To exchange data synchronously a personal computer requires specialized equipment including the installation of a synchronous communications card with a synchronous port If you will be making synchronous connections you ll find the modem easy to use Just follow the instructions in Chapter 7 INITIAL MODEM SETTINGS This manual covers the operation of three Courier models t...

Page 33: ...se the Alternative Settings after this section If necessary review your computer terminal and software documentation as well to see if your system supports the recommended settings If either your software or machine do not use the Alternative Settings after this section 1 Set your software to the highest rate your equipment and software support 19 2K 38 4K or 57 6K bits per second This sets a high...

Page 34: ...ware supports a fixed serial port rate 2 Your machine or your software does not support hardware flow control and you re using an Xmodem type file transfer protocol HO Flow control disabled factory setting Do not use software flow control H2 because the protocol control characters will be misinterpreted as flow control characters and you risk losing data BO The serial port rate switches to match t...

Page 35: ...y to HST modems Hl Hardware flow control CTS or H2 for software flow control Bl Fixed serial port rate of 9600 bps recommended for HST modems M4 Error control factory setting required or MS 6 You are calling a non MNP modem S27 16 Disable MNP handshaking A non MNP modem may misinterpret the MNP link request and prevent a successful connection This does not apply for remote V 42 modems with error c...

Page 36: ...owing command format The modem defaults to pulse dialing the T in the command enforces tone dialing The maximum number of characters in a command string is 40 ATDT phonenumber Enter To redial the number which the modem stores in a last dialed number buffer use the following command ATDL Enter LINK RATE NEGOTIATION During link negotiation handshaking the modems negotiate the highest possible rate d...

Page 37: ...nse disturbances that threaten data integrity they fall back and retrain resynchronize at the next lower speed in their fallback range 14 4K 12K 9600 7200 4800 bps If conditions remain poor Courier modems continue to fall back to the next lower speed As line improvements occur they fall forward to the next higher speed up to the link rate of the call 3 6 Quick Start ...

Page 38: ... and Courier modem communicate for example 19 2K bps The Courier modem is referred to as the DCE Data Communications Equipment Figure 4 1 indicates which commands control modem operations at the DTE DCE computer to modem and phone link modem to modem interfaces DTE Local DTE Interface RS 232 DCE Link Interface Phone Link DCE Remote DTE Interface RS 232 r i DTE DTE Interface Flow Control Link Inter...

Page 39: ... either V 32 bis modulation or HST modulation unless they are Dual Standard modems that have both capabilities By high speeds we mean calls at 16 8K HST to HST only 14 4K 12K 9600 7200 or 4800 bps The modems use identical standard modulation at 2400 bps and below Modulation Settings an The modems are set at the factory as follows V 32 bis modulation BO V 32 bis modems are always set to BO Dual Sta...

Page 40: ...nal Calls at the end of Chapter 6 The only difference you might notice is that the B1 setting Bell answer tone allows the modems to connect slightly faster Error control DTE rates flow control and other settings are the same for both HST and V 32 bis modems THROUGHPUT GUIDELINES The following guidelines should help you to make the most of your modem s advanced performance features In many instance...

Page 41: ... although overhead error control protocol information still affects overall throughput The above protocols further reduce throughput during error control ARQ connections The accuracy of the data is checked twice by the file transfer protocol and the modem To avoid redundancy use the above protocols only for non ARQ connections and only at speeds of 2400 bps and lower For the best throughput but on...

Page 42: ...r control Because of the nature of phone line channels this is never recommended for calls above 2400 bps Ml This setting is exclusive of the modems error control and is used only for Synchronous mode See Chapter 7 Synchronous Operations for instructions M2 Reserved M3 Reserved M4 Normal ARQ mode This setting is the default If the remote modem doesn t recognize the Courier s error con trol signals...

Page 43: ...13 and 14 described under Received Data Softioare Control In NOTE Flow control of data from the DTE to the modem is required under the circumstances described under Transmit Data Flow Control Hn Received Data flow control is not as critical unless for example you are writing incoming files to disk on a very slow computer Transmit Data Buffer Sizes The size of the Transmit data buffer depends on wh...

Page 44: ...nd the link rate is 14 4K bps Another example is a DTE rate of 19 2K bps and a link rate of 2400 bps NOTE The modern uses either hardware or software flow control Your software and machine must support whichever type you select although we recommend hardware flow control if possible Review the quick configuration guide that came with the modern and if necessary your software and computer manuals H...

Page 45: ...ing above in mind about software flow control WARNING If possible always use hardware flow control You may lose data if XON XOFF characters occur in the data stream from other sources They may for example come from the remote system an XON from the remote system after your modem has sent an XOFF can result in buffer overflow Ctrl S XOFF and Ctrl Q XON characters also occur in binary files and are ...

Page 46: ...pe of flow control however if your software requires a constant RTS signal WARNING Use this type of flow control only for ARQ error control calls because under error control the modems use flow control across the phone link During non ARQ connections there is no way to signal the remote modem to stop sending data If your modem stops passing data to the DTE and the remote modem keeps sending across...

Page 47: ...aracters NOTE Because of the risk described in the above warning the settings that follow are only recommended for users whose data does not include XON XOFF control characters Il The Courier acts on your typed XON XOFF commands and passes them to the remote computer Use in ARQ mode only but keep in mind that the XON XOFF characters sent to the remote computer may interfere with XON XOFF signaling...

Page 48: ...e a Courier set to 15 operates as though flow control were disabled IO it does not look for your typed XON XOFF commands However it looks for XON XOFF characters coming in over the phone link When the remote operator sends XON XOFF com mands the Courier either resumes or stops transmitting data over the link and drops the characters from the data stream If both modems are set to 15 operators at ea...

Page 49: ...to keep the modem from disabling compression K3 Selective data compression The modem negotiates only for V 42 bis compression and disables MNP Level 5 MNPS compression Use this setting to transfer 8 bit binary files ARC files and other files that are already compressed See the note below If the Courier is connecting with a V 42 or HST modem it negotiates V 42 bis compression If V 42 bis is not fea...

Page 50: ...ber to also enable Transmit Data flow control preferably hardware Hl For the phone link we recommend variable rates NO This enables the modem to switch its link rate to match the rate of a remote modem no matter what the remote modem s rate is If the link rate is fixed for example at 9600 bps N6 the modem only connects with modems operating at that rate Of course if your application requires conne...

Page 51: ...t the terminal or software regardless of the link rate For the greatest throughput set the DTE to 57 6K 38 4K or 19 2K bps for high speed calls and to at least 9600 bps for 2400 bps calls This setting is not affected by the N setting However the DTE rate must be equal to or higher than the link rate In addition this setting requires Transmit Data flow control enabled preferably hardware control Hl...

Page 52: ...ect variable or fixed rates at the link interface Variable rates allow the modem to connect with a variety of remote modems NO Variable rates Default The Courier negotiates with the remote modem for the highest possible link rate depend ing on the capabilities of the remote modem This is the recommended setting N1 9Fixed rate The modem only connects if the remote modern is operating at the same ra...

Page 53: ...cations programs require the modem to control DSR S1 Leave the modem set for DSR overridden SO unless you know that your installation requires a different setting SO DSR is always ON override Default S1 In Originate mode the modem sends DSR after it dials when it detects the remote modem s answer tone In Answer mode the modem sends DSR after it sends an answer tone S2 This option is for specialize...

Page 54: ...on reset default DO DTR override The modem operates as though DTR is always ON Dl If you issue this command before connecting with another modem you can enter online command mode during a call by toggling DTR Most communications software packages have a method for toggling DTR Dl functions similarly to the escape code except that Dl will always maintain the connection and put the modem in online c...

Page 55: ...in non volatile memory as a power on reset default CO CD override CD always ON Cl Normal CD operations The Courier sends a CD signal when it connects with another modem and drops CD on disconnect RACK CONTROLLER UNIT ACCESS Rn If the Courier modem is part of a USRobotics Total Control Modem Management System setting the modem to Rl allows an operator to use the modem to call a Rack Controller Unit...

Page 56: ... MODEMS To enable this feature type ATHl Enter to force the modem off hook Then type AT T Enter To return the modem to Command mode press any key or drop the DTE s DTR signal The modem responds OK Interface Controls 4 19 ...

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Page 58: ...defaults stored in nonvolatile memory NVRAM If DIP switch 10 is DOWN the modem resets to the factory settings stored in read only memory ROM Issue the AT F command to load the modem s factory settings Turn the modem off and power it on again At power on the modem loads either the nonvolatile memory defaults DIP switch 10 OFF or the factory settings DIP switch 10 DOWN SETTING US NG DEFAULTS The mod...

Page 59: ...n the following example The NVRAM configuration remains intact ATX7 Enter But if you want the new setting to be a default write it to NVRAM at the same time as in the following example X7 is substituted for the X4 setting stored earlier AT X7 W Enter LOADING THE FACTORY DEFAULTS F If DIP switch 10 is DOWN the factory settings are loaded at power on instead of the NVRAM defaults Factory settings fo...

Page 60: ...xecuted with the voice data switch This requires two steps 1 Store the command string 2 Program the voice data switch to execute the stored command string when pressed Write your command string to NVRAM with the ZC s command where s is the command string The command string may be up to 30 characters long spaces are not counted The following example assigns a command string that displays the link d...

Page 61: ...one W options of the Dial command The number is stored at position 0 assumed because there is non parameter AT Z T9W5551234 Enter The following example stores a long distance number at the second position We ve added spaces for readability AT Z2 1 516 555 1234 Enter The DSn command is used to dial a stored number as in this example to dial the number stored at position 2 ATDS2 Enter NOTE Do not in...

Page 62: ...Qn Numeric Mode Numeric result codes are followed by a Carriage Return but no Line Feed as in the following example where a 3 is returned for NO CARRIER ATD1234567 Enter becomes 3TD1234567 Enter Verbal Mode Verbal responses are preceded and followed by a Carriage Return and a Line Feed as in the following example ATD1234567 Enter NO CARRIER Enable suppress the display of result codes The Courier i...

Page 63: ...s of HST Dual Standard modems If your software cannot handle the added modulation information select Al or AO 23 CONNECT 9600 HST or 33 CONNECT 9600 V32 27 CONNECT 9600 ARQ HST or 37 CONNECT 9600 ARQ V32 28 CONNECT 4800 HST or 38 CONNECT 4800 V32 29 CONNECT 4800 ARQ HST or 39 CONNECT 4800 ARQ V32 30 CONNECT 7200 HST or 40 CONNECT 7200 V32 34 CONNECT 7200 ARQ HST or 44 CONNECT 7200 ARQ V32 31 CONNE...

Page 64: ... not be able to differentiate between A2 and A3 result codes A3 result codes may not be compatible with some software Result Code Sets Xn You have eight options 0 through 7 for selecting the result code subset best suited to your applications Result Codes O OK I CONNECT 2 RING 3 NO CARRIER 4 ERROR 5 CONNECT 1200 6 NO DIAL TONE 7 BUSY 8 NOANSWER 9 RESERVED 10 CONNECT 2400 11 RINGING 12 VOICE 13 CON...

Page 65: ... Dial tone not detected during the normal 2 seconds set in Register S6 Busy signal detect modem hangs up After waiting 5 seconds for an answer modem hangs up returned instead of NO CARRIER when the option is used Connection with another modem at 2400 bps The modem has dialed remote phone line is ringing Voice answer at remote site modem hangs up Connection at reported rate Same meaning for results...

Page 66: ...eset the modem operates according to the DIP switch setting The En command is not stored in nonvolatile memory as a power on reset default EO Command Mode echo OFF The modem does not display keyboard commands El Command Mode echo ON Online Local Echo Fn This command causes the modem to display a copy of the data it is transmitting to another system Many systems however return a copy of received da...

Page 67: ...eyboard In the same way you can cancel a call when you hear a busy signal You can also hear if dialing is proceeding too quickly for the system Terminate the call press any key and retype the Dial command but insert a comma or a couple of slashes to have the modem pause during the dialing process SPEAKER CONTROL Mn This command disables the speaker entirely or sets the speaker to monitor different...

Page 68: ...es and seconds as in the following example which sets the clock at the real time of 1 30 p m ATl3 13 30 00 K1 Enter At ATI3 the modem displays the real time You ll need to set the clock each time you power on the modem but the clock is not affected by the reset command ATZ TRANSMITTER ENABLE DISABLE Cn If an additional terminal and modem share the phone line for monitoring purposes the second mode...

Page 69: ...then sends any subsequent input from the DTE NOTE If the call is under MNP5 data compression destructive Breaks cause both modems to reset their data compression tables When transmission resumes the modems build new tables and the result is lower than normal throughput S REGISTERS The S Registers are used to set various timing parameters redefinition of selected ASCII characters and other configur...

Page 70: ...wing modulation and signaling standards USR HST CCITT V 32 bis CCITTV 32 V 22 bis Bell 212A CCITTV 22 CCITTV 23 CCITTV 25 Bell 103 or CCITTV 21 CCITT V 42 CCITT V 42 bis MNP CCITTV 54 16 8K 14 4K 12K 9600 7200 4800 bps Dual Standard and HST modems 14 4K 12K 9600 7200 4800 bps Dual Standard and V 32 bis modems 9600I 4800 bps Dual Standard and V 32 bis modems 2400 bps 1200 bps 1200 bps with 75 bps b...

Page 71: ... recommend leaving the modem at its link operation factory setting NO unless your application requires that you specify a fixed link rate NO allows the Courier to automatically negotiate with the remote modem for the highest possible link rate Data Format The Courier and the remote modem must use the same ten bit data format One Start bit is universal and not programmable The following table lists...

Page 72: ...e number sequence that follows The modem also executes any other commands or options included in the command line The command string may include up to 40 characters The modem counts but ignores punctuation characters such as parentheses and hyphens It does not count spaces the AT pre fix or the Carriage Return Enter key required to execute the command The following command example instructs the mo...

Page 73: ...aling type in the Dial string the Courier uses tone dialing which is faster than the default pulse type However if the phone company s central office does not have Touch Tone _ detection equipment the modem cannot break dial and contin ues to detect the dial tone If this occurs the modem automati cally reverts to pulse dialing _ Pause A comma causes a two second delay in the dial sequence The foll...

Page 74: ...se Dial and Return to Command Mode If your phone is plugged into the modem you can use this option to have the modem Auto Dial a telephone rather than a modem The Courier dials remains off hook and returns the OK message indicating it is in Command mode For example to have the modem place a voice call enter the Dial command with a semicolon ATDT5551234 Enter When the modem returns the OK result pi...

Page 75: ...in the Dial string to tell the modem to detect at least one ring wait for five seconds of silence at the other end of the call and then continue to exe cute the Dial string To use the command set the modem to X3 X4 or X7 If the modem is set to X2 or lower the modem returns an ERROR message when encountering the character in a command string If set to XS or X6 the modem hangs up when it detects a v...

Page 76: ... command where n is the number s position 0 3 in NVRAM In the first of the next two examples the phone number is stored at position 0 assumed by the modem if there is no numeric parameter ATOS Enter ATDS3 Enter You can store a partial dial sequence for example the phone number of a system to which you might want to add different codes for different extensions Store the phone number so that you don...

Page 77: ...h the last dialed number Re execute the Last Command A The A command which does not take the AT prefix or a Car riage Return redials one time A When the modem receives a command it stores the instruction in its command buffer until it receives the next AT command Note that if you ve sent the modem an additional command since the Dial command A re executes that command instead of redialing Automate...

Page 78: ...d combines the features of both the A and commands The modem enters Repeat mode as described above and redials the Dial string in the command buffer Like the A command A does not take the AT prefix or a Carriage Return A Exiting Repeat Mode Should you use or A with a command other than a Dial string abort the cycle by pressing any key To abort automated redialing be sure to press any key when the ...

Page 79: ...ch 9 DIP Switch 9 Response to OFF ON Modem goes on hook hangs up sends NO CARRIER result code factory setting Modem maintains connection Online Command mode sends OK result code The factory setting OFF forces an automatic disconnect when you issue An advantage of this is that you are not likely to inadvertently run up an all night phone bill Set DIP switch 9 ON if you want the modem to respond to ...

Page 80: ...NGING UP Hn If DIP switch 9 is ON factory setting the escape code forces the modem back to Command mode but leaves the line open If you want the modem to hang up issue the following command once the modem sends the OK result code ATH Enter If DIP switch 9 is OFF the modem automatically hangs up on receipt of the escape code AUTOMATIC ANSWERING The Courier is shipped with DIP switch 5 ON Auto Answe...

Page 81: ...ve calls when you re not at your computer Load your communications software as you normally do and set the modem to Auto Answer Also set your software s file save function to save incoming messages and or files 2 If you ve attached your phone so it can be used for con ventional calls disable Auto Answer when you are not expecting incoming data calls Otherwise your modem may answer the phone before...

Page 82: ...or the Courier HST Guard Tone Gn This setting applies only to overseas calls at 2400 or 1200 bps British phone switching systems require the modem to send an 1800 Hz guard tone after it sends an answer tone Some other European phone networks require a 550 Hz guard tone Guard tones are not used in the United States or Canada GO No guard tone U S Canada Default Gl 550 Hz guard tone follows answer to...

Page 83: ... ...

Page 84: ... data at the same speed Protocol Compatibility The devices at both ends of the link must also use the same protocol These devices are exclusive of the Courier modem which is transparent during synchronous communications The Courier s V 42 and MNP error control capabilities are not used The link protocol may be SDLC Synchronous Data Link Con trol HDLC High Level Data Link Control BISYNC Binary Sync...

Page 85: ...value after receiving an RTS signal from the DTE before responding with a CTS signal If it s necessary to change the duration of the RTS CTS delay you need to reset Register S26 See the S Register Summary in Appendix B Any restrictions about when you can call The RS 232 Interface Transmit and Receive synchronous timing pins are required at the RS 232 interface You ll need either pin 15 or pin 24 f...

Page 86: ...hile it is still in asynchronous mode NOTE Be sure that DIP switch 1 is OFF factory setting The Data Terminal Ready DTR override must be OFF so that the Courier detects when the DTE raises and lowers the DTR signal To set the modem follow the instructions for issuing commands to the modem that are in Chapter 2 Testing the Installation Commands begin with a required AT prefix and end with a require...

Page 87: ...ings are allowed HO or Hl IO RO or Rl See Chapter 4 for more information on flow control settings Transmit Clock Source Xn This setting specifies whether the Courier or your DTE generates the Transmit clock timing signals for a synchronous call Most users will require the default setting XO XO The Courier is the source of the Transmit clock timing signals and sends them to your DTE over the RS 232...

Page 88: ...he program and put the computer in Terminal mode as described in Chapter 2 Terminal mode allows you to send AT commands directly to the modem 2 Store a command string ZC s that configures the modem according to the guidelines in the previous section Setting the Modem and the Host computer s requirements In addition include the Ml command to have the modem enter synchronous mode followed by the app...

Page 89: ...page with the following modifi cations Insert SO 1 in the stored command Step 2 This sets the modem to Auto Answer Omit the Dial string shown in the same step OT and phone number If you don t wish to use a stored command and the voice data switch send the modem the appropriate configuration string ending with ML The following adapts the dial out command example Note again that all non default sett...

Page 90: ... of its read only memory ROM and returns the result to the screen This function is used only in factory testing The modem should always read the same number The modem performs a test of its random access memory RAM and returns either the OK 0 or ERROR 4 result code followed by OK when the test is completed You may want to use this command as a checkpoint if the modem appears to be malfunctioning T...

Page 91: ...11 070 S17 000 SZ3 019 S29 000 SJ5 000 S43 Z00 Figure 8 1 Sample Result of AT14 Command IS The modem displays the configuration stored in nonvolatile random access memory NVRAM as in the following example OK DHlL PULSE 80 Fl Ml X1 BALJD l9200 PARITY N UORDLEN 8 Al BO 8G0 8H1 l0 Kl LO M4 NB PO 8R1 SO TS l1 R0 SOZ 043 S03 013 S04 010 S05 008 S0b 00Z S07 0b0 S0B 002 S09 006 S10 007 Sl1 070 S12 050 S1...

Page 92: ...ession the number of characters sent may be less than the number of octets sent due to buffering operations Line Reversals only applies to HST mode operations when the modems switch the high and low speed channels At this time online fallback is only reported Enabled in HST mode Most terms used in the display are self explanatory except for the following Octets Compressed data units If the number ...

Page 93: ...ndicates the error control protocol negotiated LAPM MNP NONE or SYNC for a synchronous call Speed The last rates at which the receiverI transmitter were operating before disconnecting Disconnect Reason Possible reasons the modem hung up are as follows DTR dropped The DTE dropped the Data Terminal Ready signal terminating the call Escape code The operator sent the modem the escape code Loss of carr...

Page 94: ...it or receive data Invalid speed The modern is set to Nl or higher for a fixed link rate and the remote modern is not operating at the same rate XID Timeout The moderns failed to negotiate the V 42 Detection XID Exchange phase SABME Timeout Set Asynchronous Balance Mode Extended The moderns failed this part of V 42 link negotiation Break Timeout Incompatible processing of a Break signal occurred I...

Page 95: ...51234 LAST DIALED NUMBER INQUIRY DL At this command the modem displays the number stored in the last dialed number buffer ATDL STORED COMMAND STRING QUERY ZC At this command the modem displays the command string stored in NVRAM with the ZC s command AT ZC HELP SCREENS Courier modems provide four Help screens summaries of the basic AT command set extended ampersand command set S Register functions ...

Page 96: ...Seq n 3 Speaker Off During Dial n 0 Return On Ii ne n l Return On ine Retrain Cn n 0 Trans11 itlEr Off n l TransMi tlEr On Dn Dial a Telephone Hu11ber n 0 911 TPR W 0 DL Dial Last Phone ttu11ber DSn Dlal Stored Ph one Hu11her D HELP Diill Co1111ilnds En n 0 Ho Co1111and Echo n 1 Echo Co1111and Chars Fn n 0 Online Echo n 1 Ho Online Echo Strike a key when read n Z Return Online Speed Shirt Pulse Di...

Page 97: ...rd Tone n 2 1800 Hz Guard Ton Hn n 0 Disable TX Flow Control n l crs n Z Xorv Xoff Strike a key when ready n l nna log Loopback 11LB n 3 Digital Loopback DLB n I Grant ReHote DLB n S Deny ReHote DLB n G ReMote Digital Loopback n 7 ReMote DLB IJith Self T sl n 8 ALB IJith Self Test IJ Store Configuration Xn n 0 DCE Synchronous Clock Figure 8 5 Sample Ampersand Commands HELP Screen At ATD the Courie...

Page 98: ... Char SS Backspace Char SZ4 DSR Pulse TiMe 1 50sec S6 Uiiit TiMEY Dial Tone sec SZS Reserved S7 U 1it TiHel Carrier sec SZ6 RTSl CTS Delay TiMe VHl0sec SS CoMMa Thie sec SZ7 Bil Mapped S9 Cilrrier Detect TiHe 11 10sec 1 U21 Mode S10 Carrier Loss TiMe 1 10sec 2 Disable TCl1 S11 Dial Tone Spacing Msec I Disable U3Z S1Z Escape Code Tl He V50sec 8 Dls ible Z100h z S13 Bit 11apped 1 Disilble MNP Handsh...

Page 99: ... ...

Page 100: ...maries and Tables The RS 232 Interface B 2 Front Panel Indicators B 4 DIP Switch Summary B 6 Default Settings B 9 S Register Summary B 12 ASCII Chart B 21 Appendix C Alphabetical Command Summary Requirements C 1 Basic Command Set C 1 Ampersand Command Set C 6 Percent Command Set C 11 Remote Access Commands C 11 Appendix D Problems and Solutions D 1 Appendix E Fax and Other Operations Fax Operation...

Page 101: ...og Loopback Tl TS F 2 T2 F 4 Digital Loopback T3 F 4 T4 TS F 5 Remote Digital Loopback T6 T7 F 5 Testing with Register 516 F 8 Analog Loopback 516 10 F 8 Dial Test 516 2 F 9 Test Pattern 516 4 F 9 Remote Digital Loopback 516 8 F 10 Appendix G Glossary G 1 Appendix H Technical Specifications H 1 Index ...

Page 102: ...the modem is attached DTE rate is the same as serial port rate LINK NEGOTIAT ON HANDSHAKING HST Mode During high speed link negotiation timing and procedures differ for HST or V 32 bis modulation as follows Serial port rate 57 6K 38 4K 19 2K 9600 bps 57 6K 38 4K or 19 2K required for 16 BK or 14 4K connections Modem settings Bl Bl Hl H2 H3 M4 MS NO 1 The modems begin handshaking by training synchr...

Page 103: ...Both modems must be set as follows High speed handshaking requires a fixed link rate the modem only connects if the remote modem is operating at the same link rate 9600 N6 12K N7 14 4K bps NS or 16 SK bps N9 Serial port rate 57 6K 3S 4K 19 2K 9600 bps 57 6K 3S 4K or 19 2K required for 16 SK or 14 4K connections Modem settings Bl Bl Hl I H2 H3 MO N6 N7I NS N9 HST Mode Error Control Disabled If erro...

Page 104: ...ection This proprietary handshaking is described after the next section under USRobotics V 32 bis to V 32 bis V 32 bis NOTE High speed calls are highly vulnerable to errors unless the data is protected by error control The operations described below take place even if one of the modems is not set for error control thereby prohibiting error control for the call Serial port rate 57 6K 38 4K 19 2K bp...

Page 105: ...se tones if the modem is to answer older dumb V 32 modems Register 528 is used to modify the duration of these extra V 32 tones See 528 in Appendix B USRobotics V 32 bis to V 32 bis 1 The modems first negotiate a V 42 error control connection Speed negotiation is part of the V 42 detection LAPM sequence If they fail to make a V 42 connection these modems follow the procedures described under V 32 ...

Page 106: ...de for that call only if the other modem is operating in HST mode ERROR CONTROL AND THROUGHPUT Overview Error control is available for calls at 1200 bps and above It can be disabled although high speed calls above 2400 bps should always be under error control The operations defined in an error control protocol include the following Establishment of compatibility Data frame formatting Error detecti...

Page 107: ...or control isn t possible In HST asymmetrical mode USRobotics modems use a proprietary scheme similar to MNP Data Compression If the modems successfully establish a V 42 connection they also negotiate for V 42 bis data compression If they successfully establish an MNP connection they negotiate for MNP5 data compression The type of compression for a call if any is reported in the ATI6 display Modem...

Page 108: ...ch lessens throughput The additional data is stripped when the file is decompressed by the remote modem When transferring such files it s best to set the modem to K3 this allows V 42 bis compression to work dynamically with the compressed data but disables MNP5 Flow Control Flow control of data from the computer is required under error control for two reasons 1 The transmitting modem buffers a cop...

Page 109: ... this appendix 2 MNPS compression is disabled for files that are already compressed and 8 bit binary files that appear to the modem to be already compressed MNPS is disabled by setting the modem to K3 3 The file transfer is not slowed down by a file transfer protocol Many non text files require a file transfer protocol but the results vary For example certain public domain file transfer protocols ...

Page 110: ...flow control XON XOFF signaling Achievable Throughput The table below indicates the maximum throughput in charac ters per second cps that can normally be expected under the following conditions Connection Oink rate of 14 4K bps DTE rate set at 57 6K bps modem set to Bl V 42 bis compression negotiated for the call and the default size 11 bit 2048 entry dictionary Straight data e g not already compr...

Page 111: ...e Assembler or Compiler listing Text file Binary file EXE Binary file COM ARC files common on BBS s Random binary 8 bit Throughput cps when set to 16 SK bps MNP5 V 42 bis 3360 2713 3063 2538 2800 2450 2625 1750 1925 1703 1838 4480 5760 3967 5760 2368 3033 2392 2683 1983 1983 We recommend setting the modem to K3 when transferring these types of files See the note attached to the previous table A 1O...

Page 112: ...OURIER HIGH SPEED MODEMS APPENDIX 8 SUMMARIES AND TABLES The RS 232 Interface with Pin Definitions Front Panel Indicators DIP Switch Summary Default Settings S Register Summary ASCII Chart Summaries and Tables B 1 ...

Page 113: ...le computers should be wired at the computer end of the cable as shown in the DB 9 column If you re using an Apple computer ask your dealer for the correct modem cable for your Apple computer model Signal Flow DB 25 DB 9 Circuit Function DTE DCE 1 AA Chassis Ground both directions 2 3 BA Transmitted Data toDCE 3 2 BB Received Data to DTE 4 7 CA Request to Send toDCE 5 8 CB Clear to Send to DTE 6 6...

Page 114: ...dem source assigned to pin 15 See Chapter 7 for more detailed information Additional Flow Control Functions If your computer and software support Clear to Send and you wish to use Transmit Data hardware flow control Hl Pin 5 DB 25 or Pin 8 DB 9 is required If your computer and software support Request to Send and you wish to use Received Data hardware flow control R2 Pin 4 DB 25 or Pin 7 DB 9 is r...

Page 115: ...ting and the Courier receives a valid data signal carrier from a remote modem indicating that data transmission is possible Also ON when the CD override is on DIP switch 6 ON OH Off Hook ON when the Courier takes control of the phone line to establish a data link RD Received Data Flashes when the modem sends result codes or passes received data bits to the computer or terminal SD Send Data Flashes...

Page 116: ...en Trans mit Data hardware flow control is enabled Hl H3 Always ON during synchronous connections SYN Synchronous ON when the modem is set to Ml and Mode enters synchronous mode ARQ Error Control Data Mode Automatic Repeat Request ON FAX Fax Operations when the Courier is set to M4 or MS and successfully connects with another modem under error control Flashes randomly when the Courier retransmits ...

Page 117: ...ts read by the Courier when it is turned on If changed when the modem is on switches 2 5 7 and 9 require the ATZ software reset command to initiate the new settings If you ve set switch 8 OFF to disable command recognition and want to return the modem to Smart mode so that it responds to commands you ll have to power off the modem reset switch 8 ON and power on the modem again The remaining hardwa...

Page 118: ...onnect ON CD always ON Override 7 OFF Auxiliary DIP Switch 3 ON OFF Result codes in Originate and Answer mode ON Result codes in Answer mode disabled 8 ON AT Command Set Recognition OFF Command recognition disabled Dumb Mode ON Recognition enabled Smart mode 9 OFF Escape Code Response OFF Modem hangs up returns to Command mode sends NO CARRIER result ON Modem maintains connection returns to Comman...

Page 119: ...ransmit Receive Pin Assignments OFF Normal assignments see Pin Assignments in Appendix B 1 ON Reversed Transmit Receive pins The need to change this switch setting is rare Carefully review your computer or terminal documentation before setting this switch ON 8 8 Summaries and Tables ...

Page 120: ...ettings at any time use the ATIS command Tables on the next two pages list the options you can store in NVRAM including S Register settings If DIP switch 10 is ON at power on the factory settings listed in the table are loaded instead The first time the modem is turned on the NVRAM settings are the same as the factory settings The following command example substitutes several user defined defaults...

Page 121: ... echo Fl Disabled Speaker control Ml ON during dial through connect Remote Digital Loopback RDL TS DenyRDL Normal Leased line LO Normal phone line Data Set Ready override SO Enabled Synchronous clock source XO Modem transmitter Break handling Yl Clear buffer send immediately Stored telephone number Z0 3 0 Blank Pulse dial make break ratio PO U S I Canada Guard tone GO U S Canada Rack Controller Un...

Page 122: ...ctions 0 SI9 Inactivity hang up timer 0 S2I Break length I I IOOth msec 10 S22 XON character I7 S23 XOFF character I9 S24 Pulsed DSR duration 2 100th sec ISO S26 RTSI CTS delay time 1 100th sec 0 S27 Bit mapped functions 0 S28 V 32 handshake time I 10th sec 8 S29 V 2I handshake time I 10th sec 20 532 Talk Data Switch Options 1 S34 Bit mapped functions 0 S38 Disconnect wait time sec 0 S4I Allowable...

Page 123: ...he number of rings on which to Switch 5 answer when in Auto Answer Mode SO O disables Auto Answer the same as DIP switch 5 ON factory setting SO l enables Auto Answer and the modem answers on the first ring Sl 0 Counts and stores the number of rings from an incoming call S2 43 Stores the ASCII decimal code for the escape code character Default character is A value of 128 255 disables the escape co...

Page 124: ...ognition by the Courier SlO 14 Sets the duration in tenths of a second that the modem waits after loss of carrier before hanging up This guard time allows the modem to distinguish between a line hit or other disturbance that momentarily breaks the connection from a true discon nect hanging up by the remote modem While we do not recommend connecting the modem to a line with call waiting if you have...

Page 125: ...Reverse normal Auto Answer operation on incoming RING enter Originate Mode and look for Answer tone 2 4 Disable 250 msec pause before result code display 3 8 On DTR signal Auto Dial the number stored in NVRAM at position 0 4 16 At power on reset Auto Dial number stored in NVRAM at position 0 5 32 Disable HST used for testing V 32 bis in Dual Standard modems 6 64 Disable MNP Level 3 used for testin...

Page 126: ...earlier 2400 bps MNP modems not made by USRobotics or Microcom were not fully compatible with the MNP protocol If you have difficulty making a successful 2400 bps MNP connection with a remote MNP modem it may be because of this incompati bility Set S15 to 64 and try again to make the connection 7 128 Custom applications only The default 1 SK byte non ARQ buffer allows data transfer with X and Ymod...

Page 127: ...seconds before the modem automatically times out and terminates the test S19 0 Sets the duration in minutes for the Inactivity Timer The timer activates when there is no data activity on the phone line and at the timeout the modem hangs up Sl9 0 disables the timer S20 0 Reserved S21 10 Sets in 10 millisecond units the length of Breaks sent from the modem to the DTE Applies to ARQ mode only S22 17 ...

Page 128: ...s 1 2 Enable unencoded non trellis coded modulation in V 32 mode this option is part of the CCITT V 32 recommendation but is rarely used 2 4 Disable V 32 modulation used for testing HST modulation in Dual Standard modems 3 8 Disable 2100 Hz answer tone to allow two V 42 modems to connect more quickly 4 16 See below 5 32 See below 6 64 Reserved 7 128 Unusual software incompati bility Some software ...

Page 129: ... V 32 modems additional time to connect in V 32 mode before timing out If there is difficulty answering older manually operated V 32 modems for example modems that require a button to be pushed in order to dial try lengthening the duration of the extra tones Setting S28 to zero eliminates the extra tones resulting in a faster connect time i for example the modem is set to use V 21 modulation 300 b...

Page 130: ... Busy out phone line toggle Bit mapped register See instructions for S13 Bit Value Result 0 1 Disable V 32 bis Used for 1 2 troubleshooting USRobotics Technical Support may require that you disable V 32 bis for testing purposes 2 Disable the modem s enhanced proprietary V 32 bis modula tion Used for troubleshooting 4 Disable the faster retrains that occur during proprietary V 32 bis modulation Use...

Page 131: ...lowable remote access login attempts thus enabling or disabling remote access The default setting of zero allows no remote login attempts thus disabling remote access A value of 1 or greater enables remote access If the number of unsuccessful login attempts exceeds the limit set by this register the modem returns online and any further login attempts during the remainder of that connection are ref...

Page 132: ...12 oc FF 44 2C 76 4C L 108 6C I 13 OD CR 45 20 77 40 M 109 60 m 14 OE so 46 2E 78 4E N 110 6E n 15 OF SI 47 2F I 79 4F 0 111 6F 0 16 10 OLE 48 30 0 80 50 p 112 70 p 17 11 XON 49 31 1 81 51 Q 113 71 q 18 12 DC2 50 32 2 82 52 R 114 72 r 19 13 XOFF 51 33 3 83 53 s 115 73 s 20 14 DC4 52 34 4 84 54 T 116 74 t 21 15 NAK 53 35 5 85 55 u 117 75 u 22 16 SYN 54 36 6 86 56 v 118 76 v 23 17 ETB 55 37 7 87 57 ...

Page 133: ... ...

Page 134: ...ctuation such as hyphens and parentheses 4 A missing numeric parameter is assumed to be zero as in the command to hang up ATH Enter is the equivalent of ATHO Enter BASIC COMMAND SET See the Extended Command Summary that follows this Basic Set See the Percent Command Summary that follows the Extended Command Summary A Force Answer mode when the modem hasn t received an incoming call A Re execute th...

Page 135: ...rier modems answering overseas calls at 1200 bps and above B1 a HST modulation no V 32 bis answer tones Courier HST Default Courier HST Dual Standard Default Also calls but does not answer V 32 bis modems Courier V 32 bis Calls V 32 bis modems but does not answer V 32 bis calls b Bell answer tone United States and Canada Cn Transmitter enabled disabled CO Transmitter disabled receive only conditio...

Page 136: ...mote system Fl Local echo OFF Default Sometimes called Full Duplex Receiving system may send a remote echo of data it receives Hn On off hook control In Kn HO Hang up go on hook Hl Go off hook Inquiry IO Display product code I1 I2 Display results of ROM checksum Display results of RAM test 13 Display call duration or real time see Kn I4 Display current modem settings IS Display nonvolatile random ...

Page 137: ...y for testing purposes P Pulse dial Default Qn Quiet mode result codes displayed suppressed DIP switch 3 is factory set for result code display QO Result codes displayed Ql Result codes suppressed quiet Q2 Result codes suppressed in Answer mode Sr n Set S Register value r is any S Register n must be a decimal number between 0 and 255 Sr b n Alternative command for setting bit mapped registers r is...

Page 138: ... Answer Fast Dial NOTE Use AO or Al to disable enable the following ARQ result codes The default is Al ARQ codes messages 14to19 enabled 14 CONNECTI ARQ 22 CONNECT 12000 ARQ 15 CONNECT 1200 ARQ 24 CONNECT 7200 ARQ 16 CONNECT 2400 ARQ 26 CONNECT 14400 ARQ 17I CONNECT 9600I ARQ 47 CONNECT16800 ARQ 19I CONNECT 4800I ARQ Use A2 to add HST or V 32 modulation indicators as well as ARQ and non ARQ status...

Page 139: ...inuously until canceled by pressing any key If used in a Dial string automated redialing terminates after ten attempts I Slash Pause 125 milliseconds Help Basic command summary request Help Extended command summary request D Help Dial command summary request S Help S Register summary request Ctrl S StopI restart display of Help screens Ctrl C Cancel display of Help screens or Ctrl K AMPERSAND COMM...

Page 140: ...1 is factory set OFF for normal DTR operations and the override is disabled DO DTR override DTR always ON Dl If you issue this command before connecting with another modem you can enter online command mode during a call by toggling DTR Most communications software packages have a method for toggling DTR Dl functions similarly to the escape code except that Dl will always maintain the connection an...

Page 141: ...ontrol In Received Data software flow control IO Flow control disabled Default 11 XON XOFF to local modem and remote computer 12 XON XOFF to local modem only 13 Host mode Hewlett Packard protocol 14 Terminal mode Hewlett Packard protocol 15 Same as 12 in ARQ mode In non ARQ mode XON XOFF to remote modem for link flow control Kn Data compression KO Disabled Kl Auto enable disable Default Disabled i...

Page 142: ... connection cannot be made Nn Link Rate DCE DCE variable or fixed With fixed link rate modem hangs up if called or calling modem is operating at a different rate NO Variable link operations Default Modem negotiates highest possible link rate with remote modem Nl 300 bps N2 1200 bps N3 2400 bps N4 4800 bps _ NS 7200 bps N6 9600 bps N7 12K bps NB 14 4K bps N9 16 8K bps HST to HST only Pn Pulse diali...

Page 143: ...d CTS following Carrier Detect CD S3 This is the same as S2 but without CTS following CD Tn Modem testing TO End test Tl Initiate Analog Loopback AL testing T2 Reserved T3 Initiate Local Digital Loopback LDL testing T4 Grant Remote Digital Loopback RDL TS Prohibit RDL T6 Initiate RDL testing T7 Initiate RDL with self test and error correction TS Initiate AL with self test and error correction W Wr...

Page 144: ...eived from DTE Zn s Write the following Dial string s to NVRAM at position n n 0 3 Zn Display the phone number stored in NVRAM at position n n 0 3 ZC s Write the following command string s to NVRAM ZC Display the stored command string PERCENT COMMAND SET Rn Rack Controller Unit RCU access For use with USRobotics Total Control Modem Management Systems RO Normal operations RCU access disabled Defaul...

Page 145: ...mand to cancel any configuration changes made during remote access and restore the original configuration C2 Execute configuration Use this command to force configuration changes to take effect immediately during the current connection We do not recommend forcing immediate configuration changes as this can result in an unreliable connection or even a loss of connection Fn Configure data format FO ...

Page 146: ... sure you re typing in either upper case or lower case letters not a combination and that you press the Enter key 2 If you re using a computer make sure it is in Terminal Mode This is a communications software function See Testing the Modem in Chapter 2 3 Check to see that your terminal or software is set to the correct bit rate and word length 7 bits with or without a parity bit or 8 bits and no ...

Page 147: ...and sending the modem the ATZ command or by sending the modem the ATEO command Your computer Reacts as though a data link has been established but no call has been received DIP switch 6 is set ON at the factory for Carrier Detect CD override but your system may require that the override be turned OFF Review your terminal s manual the Settings Supplement that came with the modem or your communicati...

Page 148: ...em the correct setting 4 If your modem is attempting to answer a V 32 call you may need to lengthen the extra V 32 answer tones See S28 in Appendix 5 5 Depending on your model make sure the modem at the other end of the line is HST compatible V 32 bis compatible at 14 4K bps or V 32 compatible at 9600 bps V 22 bis compatible at 2400 bps Bell 212A compatible at 1200 bps or Bell 103 compatible at 30...

Page 149: ... the modem you first tried to call Random or garbage characters Check to make sure that both modems are set to the same bit rate word length parity and number of Stop bits If the modem is set to a fixed DTE rate Bl and your software is fixed at 19 2K or 38 4K bps the reason may be one of the following 1 Your computer may not support the high rate If this is the case fix your software rate at 9600 ...

Page 150: ...lly to see if you ve missed something 2 Call or visit your dealer Chances are your dealer will be able to give you the assistance you need This is much more efficient and time saving than returning the modem to USRobotics 3 If your dealer can t clear up your difficulties call the USRobotics Technical Support Department at 800 982 5151 or send a Fax to 708 982 0823 Our Service Representatives will ...

Page 151: ...el as well c Ship the well packed modem to the following address Technical Support Department U S Robotics Inc 8100 North McCormick Boulevard Skokie Illinois 60076 d Please note that USRobotics will not accept packages sent COD so be sure to send the modem postage paid e USRobotics will repair your modem and return it to you via United Parcel Service D 6 Problems and Solutions ...

Page 152: ...MODEMS APPENDIX E FAX AND OTHER OPERATIONS Fax Operations Voice Data Remote Access High Speed Low Speed Protocol Dedicated and Leased Line Operations Hewlett Packard 3000 Installations Ml MIC Operations Fax and Other Operations E 1 ...

Page 153: ... is currently in use the following command AT FCLASS The modem will return a value of 0 to indicate data mode or 1 to indicate fax mode NOTE Whenever the fax modem is reset by using the ATZ command by toggling the DTR signal or by turning the power off and on the modem will be set to data mode A NOTE TO PROGRAMMERS If you want to know more about the supported fax commands refer to the standard for...

Page 154: ...to the second modular jack of the modem so it s available for voice calls You can also switch between the phone and modem during a call Users of Courier modems have always been able to phone and make arrangements with another user before turning control of the call over to the modems However it was difficult to switch from data to voice Now if the remote modem has handset exclusion you can change ...

Page 155: ...dem it doesn t matter who made the phone call But one modem must first enter Originate mode and the other then enter Answer mode 2 Without hanging up the phone press the voice data switch If 532 is set to 2 Answer mode press the voice data switch immediately after the remote user forces the remote modem off hook in Originate mode 3 The other party should force the remote modem off hook in Answer m...

Page 156: ...m go off hook in Answer mode The following command is used to do this ATA Enter 4 If the remote modem also has handset exclusion leave both phones off hook in case you wish to switch back again to voice after your data transfer If the remote modem doesn t have handset exclusion switching back to voice may not be successful If you don t want to switch back to voice later hang up both phones as soon...

Page 157: ...ata Answer Mode ATA Appendix C 3 Redial Last Number ATDL Chapter 6 4 Dial Number Stored at position 0 ATDSO Chapter 6 5 Auto Answer On Off Toggle ATSO O or 1 Chapter 6 6 Reset Modem ATZ Chapter 5 7 Initiate Remote Digital Loopback AT T6 516 8 Appendix F 8 Busy Out Phone Line Toggle 9 Execute Stored Command String AT ZC s Chapter 5 E 6 Fax and Other Operations ...

Page 158: ...or remote access Set Register 541 for a value of 1 or greater S41 is used to set the number of allowable login attempts as explained later A setting of zero allows no login attempts and thus disables remote access Press and hold down the voice data switch while pow ering on the modem Pressing the switch during power on causes the modem to perform its normal self test enables Auto Answer enables Re...

Page 159: ...tempts is set to 1 or greater remote access is enabled If the number of unsuccessful login attempts exceeds the limit set by S41 the modem returns online and any further login attempts during the remainder of that connection are refused Disabling Password Security If you want to disable an assigned password and thereby dis able remote access security use the following command format AT PO Enter or...

Page 160: ...tics Courier 16800 HST Dual Standard Remote Serial Number OOOOOOA000000001 4 At this point if password security is active the caller is prompted for the password Password Ctrl C to cancel As described earlier in Password Security entering the pass word assigned with PO allows viewing privileges only Entering the password assigned with Pl allows viewing and configuration privileges Note that there ...

Page 161: ... communicate with the Courier as if you were typing commands at its attached ter minal or computer Depending on your access privileges you can use the regular Courier AT commands If you have view privileges only with Password 0 you can use any of the view commands described in Chapter 8 If you have view and configure privileges with Password 1 you can use any of the Courier commands except those c...

Page 162: ...g C values Cl Restore configuration Use this command to cancel any configuration changes made during remote access and restore the original configuration However commands that have been written to NVRAM with W will not be restored to their previous settings Additionally if you have forced immediate configuration changes with C2 those changes cannot be reversed with Cl C2 Execute configuration Use ...

Page 163: ...can type the following commands without pausing after each one a password ABCDEF Enter a configuration string AT Hl R2 W Enter and a request for an information screen ATIS Enter The maximum number of characters between carriage returns is 40 Ending a Remote Access Session You can issue one of three commands to end a remote access session ATZ resets the Courier modem and terminates the connection A...

Page 164: ...higher it signals the DTE with one of the following result codes or the optional result codes selected with the An command CONNECT 300 bps CONNECT 1200 1200 bps CONNECT 2400 2400 bps CONNECT 4800 4800 bps CONNECT 7200 7200 bps CONNECT 9600 9600 bps CONNECT 12000 12 000 bps CONNECT 14400 14 400 bps CONNECT 16800 16 800 bps HST to HST connections only The modem sends the result code at its previous ...

Page 165: ...200 CONNECT 19 200 3 Data link is established 300 Data transfer takes place 4 Data session is over NO CARRIER 300 Call is ended loss of carrier 5 2400 bps call comes in RING 300 CONNECT 2400 300 6 Data link is established 2400 Data transfer takes place 7 Data session is over NO CARRIER 2400 Call is ended loss of carrier 8 14 4K bps call comes in RING 2400 CONNECT 14400 2400 9 Data link is establis...

Page 166: ...em responds RING and CONNECT 2400 These message are sent at the current bit rate of 300 bps 6 The computer receiving the CONNECT 2400 message adjusts accordingly to the higher bit rate The modem also shifts to 2400 bps 7 The 2400 bps data session is terminated the modem sends the computer the message NO CARRIER at 2400 bps 8 A 14 400 bps call comes in The modem responds RING and CONNECT 14400 Thes...

Page 167: ...telephone company request a 2 wire line the type of line the modem is designed to work with If the telephone company only makes a 4 wire line available you ll need a 4 wire to 2 wire converter at each end of the connection If the phone company does not install the con verters you will have to supply them For optimal operations we recommend that the physical length of these lines not exceed 5 miles...

Page 168: ...the Courier interprets any keyboard data entry including an accidental key stroke as a key press abort and hangs up Delaying CTS until after carrier detection prevents this from happening for example if you are typing data to the remote modem when the modems momentarily disconnect and begin to reconnect However you have to set the modem for hardware flow control H1 If your software or machine does...

Page 169: ...faults including L1 The modems go off hook and establish the connection NOTE If the modems cannot restore the connection and you could not set the modem to 52 the reason could be a key press abort If the problem persists however you may need to call your telephone company to have them check your line E 18 Fax and Other Operations ...

Page 170: ...ier modems manage this ENQ ACK protocol so that communication is speeded up thereby enabling HP terminals to achieve high speeds on dial up lines Special flow control settings using the I command are required for HP users These settings apply to ARQ connections only and to Courier modems set to either BO or Bl Disregard other Courier flow control commands Set the Courier to Host mode if it is atta...

Page 171: ...s in the phone line connector The modem s OH Off Hook status light or LED goes on when the modem goes off hook TROUBLESHOOTING You may find that the modem does not respond to Ml MIC closure which you can monitor by observing the LED Or the modem may fail to go back on hook when the DTE drops the Data Terminal Ready DTR signal The probable reason for either of these conditions is that your phone eq...

Page 172: ...6 J4Ell STANDARD Ml MIC WIRING Figure E 1 Courier Modem Board J6 J4 8 The jumpers are black shunts that cover two out of three upright metal contacts As shown in the figure the modem is shipped with the jumpers over the two contacts on each switch that are closest to the front panel The third contact on each switch is exposed Lift off the jumpers from J4 and J6 Reverse the positions shown in Figur...

Page 173: ...you dialed a number listen for an answer tone from the remote modem Then drop the DTR signal The modem should go on hook and the OH status light should go off 12 If closure is not working properly review the steps in this appendix Be sure the jumper switches are in the reverse position of those in Figure E 1 If you still have problems there may be a problem with the phone cable Or there may be a p...

Page 174: ... testing If the modem is detecting errors and retransmitting the affected data your results will be invalid During testing the MR status light flashes Ending a Test TO S18 Issuing the TO command terminates a test Alternatively set Register 518 to a specified number of seconds for example 518 10 When the 10 seconds are up the modem automatically ends the test and returns to Command mode If the test...

Page 175: ...ult NOTE HST or Dual Standard modems must be tested at 2400 bps or lower to avoid asymmetrical modulation at higher speeds 1 If you are testing an HST or Dual Standard modem set your terminal or software to 2400 bps 2 The modem must be in Command mode If you wish set Register 518 as a test timer as explained earlier 3 Send the modem the following command AT MO T1 Enter The modem disables error con...

Page 176: ...mitter and loop it back to the receiver An internal error detector counts any errors and when the test is ended sends the number of errors or 000 no errors to the screen Since you don t type anything during this test and the modem does not send anything to the screen this option verifies only the modem If there are no errors but your problem continues it may be at the computer interface 1 If you a...

Page 177: ...odem or the telephone channel Figure F 2 shows the data flow during DL testing Local Modern Remote Modem Figure F 2 Data Flow During Digital Loopback NOTE This test requires the modem to establish a connection and return to online command mode in response to the escape code DIP switch 9 must be set ON so that the modem does not hang up on receipt of the escape code After you change the switch issu...

Page 178: ...ve issued an invalid command 5 Reset DIP switch 9 OFF if you normally use the factory default Reset the modem to M4 unless you used the reset command ATZ The T4 option causes the modem to grant a remote modem s request for a Remote Digital Loopback test The TS option cancels T4 and the modem fails to recognize such a request This is the default so that your modem isn t subject to another user call...

Page 179: ...set the S18 timer Establish a connection with the remote modem If you haven t already done so arrange with the remote user to cooperate with your testing and if necessary set the remote modem to acknowledge the RDL request For example older USRobotics high speed modems need to be set to 516 8 2 Bring the Modem back to Command mode with the escape code Send it the AT T6 command The modem enters RDL...

Page 180: ...user to cooperate with your testing and if necessary set the remote modem to acknowledge the RDL request For example older USRobotics high speed modems need to be set to S16 8 2 Bring the modem back to Command mode with the escape code Then send it the AT T7 command The modem enters RDL mode and the MR status light flashes The modem sends its internal test pattern to the remote _ modem which loops...

Page 181: ...ng instead To perform RDL with a USRobotics modem that does not use the T test repertoire that modem should be set to S16 8 before it can grant RDL testing ANALOG LOOPBACK AL S 16 1D As with the T AL test do not attempt this test under error control HST and Dual Standard modems should be tested at 2400 bps or lower to avoid asymmetrical modulation at higher speeds To use the modem s Test Pattern S...

Page 182: ...g Analog Loopback AL or Remote Digital Loopback RDL using T commands or 516 The test pattern is available at all speeds At 300 bps the modem s DTE rate must be fixed Bl and the link rate fixed at 300 bps Nl At rates over 9600 bps just set the modern for a fixed DTE rate Bl To use the test pattern during AL testing with 516 type the following command The test pattern is sent through the loopback AT...

Page 183: ...ue an ATZ command to initiate the new switch setting 2 Set the software to 2400 or 1200 bps The CCITT specified RDL signals are defined only for connections at 2400 or 1200 bps 3 Disable error control by setting the modem to MO Then establish a connection with the remote modem 4 Bring the modem back to Command mode by sending it the escape code one second of no data three pluses and another second...

Page 184: ...mally would and reset the modem to its normal error control setting M4 or M5 Or if you wish to resume data transmission with the remote modem add the 0 command to the ATS16 0 string to return the modem online Keep in mind however that error control is disabled Because error control is negotiated during the connection sequence its status cannot be changed until the modem is back on hook and in Comm...

Page 185: ... ...

Page 186: ...hich is in Originate mode Application application program ARQ A computer program designed to perform a specific function such as a word processor or a spreadsheet Automatic Repeat Request A general term for error control protocols which feature error detection and automatic retrans mission of defective blocks of data See HST MNP and V 42 ASCII American Standard Code for Information Interchange A 7...

Page 187: ...e numbers over the phone system without the use of a telephone transmitter Baud Rate The number of discrete signal events per second occurring on a communications channel Although not technically accurate baud rate is commonly used to mean bit rate Bisync Binary Synchronous Control An earlier protocol developed by IBM for software applications and communicating devices operating in synchronous env...

Page 188: ...he term usually refers to 8 bit units or characters 1 kilobyte K is equal to 1 024 bytes or characters 64K indicates 65 536 bytes or characters Carrier A continuous frequency capable of being either modulated or impressed with another information carrying signal Carriers are generated and maintained by modems via the transmission lines of the telephone companies CC TT An international organization...

Page 189: ...d receiving modems The sending modem inserts the results of its computation in each data block in the form of a CRC code The receiving modem compares its results with the received CRC code and responds with either a positive or negative acknowl edgment In the ARQ protocol implemented in USRobotics high speed modems the receiving modem accepts no more data until a defective block is received correc...

Page 190: ... not go through telephone company switching equipment Default Any setting assumed at startup or reset by the computer s soft ware and attached devices and operational until changed by the user Digital Loopback A test that checks the modem s RS 232 interface and the cable that connects the terminal or computer and the modem The modem receives data in the form of digital signals from the computer or...

Page 191: ...transmission of errored frames ARQ Facsimile A method for transmitting the image on a printed page from one point to another Commonly referred to as Fax Fax Mode The mode in which the fax modem is capable of sending and receiving files in a facsimile format Flow Control A mechanism that compensates for differences in the flow of data input to and output from a modem or other device Frame A data co...

Page 192: ...gh speed modems HST incorporates trellis coded modulation for greater immunity from variable phone line conditions and asym metrical modulation for more efficient use of the phone channel at speeds of 4800 bps and above HST also incorporates MNP compatible error control procedures adapted to asymmetrical modulation Hertz a frequency measurement unit used internationally to indicate one cycle per s...

Page 193: ...of errored frames USRobotics modems use MNP Levels 1 4 and Level 5 data com pression MNP Levels 1 4 have been incorporated into CCITT Recommendation V 42 Compare HST Modem A device that transmits receives computer data through a com munications channel such as radio or telephone lines The Courier is a telephone channel modem that modulates or trans forms digital signals from a computer into the an...

Page 194: ...that checks the validity of a trans mitted character Character checking has been surpassed by more reliable and efficient forms of block checking including Xmodem type protocols and the ARQ protocol implemented in Courier modems The same type of parity must be used by two communicating computers or both may omit parity When parity is used a parity bit is added to each transmitted character The bit...

Page 195: ... system and displayed on the screen Remote echo ing is a function of the remote system Read Only Memory Permanent memory not user pro grammable The Courier s factory settings are stored in ROM and can be read loaded into RAM as an operational configura tion if DIP switch SlO is ON at power on Serial Transmission The transfer of data characters one bit at a time sequentially using a single electric...

Page 196: ...omputer acts as if it were a stan dard terminal such as a teletypewriter rather than a data proces sor Keyboard entries go directly to the modem whether the entry is a modem command or data to be transmitted over the phone lines Received data is output directly to the screen The more popular communications software products control Terminal mode as well as enable more complex operations including ...

Page 197: ... with the BO command so that they use the V 25 2100 Hz tone when answer ing overseas calls V 27 ter V 29 V 32 A CCITT standard for facsimile operations that specifies modulation at 4800 bps with fallback to 2400 bps A CCITT standard for facsimile operations that specifies modulation at 9600 bps with fallback to 7200 bps A CCITT standard for modem communications at 9600 bps and 4800 bps V 32 modems...

Page 198: ...umber of bits in a data character without parity start or stop bits Xmodem The first of a family of error control software protocols used to transfer files between modems These protocols are in the public domain and are available from many bulletin board services XON XOFF Standard ASCII control characters used to tell an intelligent device to stopI resume transmitting data In most systems typing C...

Page 199: ... ...

Page 200: ... Modulation TCM 4800 bps synchronous asynchronous Quadrature Amplitude Modulation QAM ADDITIONAL COMPATIBILITY FEATURES CCITT V 25 2100 Hz tone CCITT V 23 1200 bps asymmetrical 1200 75 bps Frequency Shift Keying FSK CCITT V 22 bis 2400 bps synchronous asynchronous Quadrature Amplitude Modulation QAM CCITT V 22 1200 bps synchronous asynchronous Differential Phase Shift Keying DPSK Bell 212A 1200 bp...

Page 201: ...rminal modem interface Superset of industry standard AT command set S registers DIP switches Optional Ml MIC closure Optional pulsed DSR DTE SERIAL PORT RATES 57 6K 38 4K 19 2K 9600 4800 2400 1200 300 110 bps LINK RATES Data Mode 16 8K HST only 14 4K 12K 9600 7200 4800 2400 1200 300 110 bps Fax Mode 9600 7200 4800 2400 300 bps ADAPTIVE SPEED LEVELING 16 8K HST only 14 4K 12K 9600 7200 4800 bps PHO...

Page 202: ...ntification and control Stop transmission and pause 10ms Wait for silence 10 ms FTM n 3 24 48 72 96 Transmit data with carrier FRM n 3 24 48 72 96 Receive data with carrier FTH n 3 24 48 72 96 Transmit HDLC data with carrier FRH n 3 24 48 72 96 Receive HDLC data with carrier Dialing Rotary pulse 0 9 Touch Tone DTMF 0 9 a z when in Quote Mode DATA FORMAT Binary serial defaults to 7 bit word length ...

Page 203: ... cs Clear to Send SYN Synchronous Mode ARQ Error control connection established FLOW CONTROL BUFFERS Transmit Buffer Error control 3 25k bytes Non Error control 1 Sk bytes 128 byte option Receive Buffer 2K bytes COMMAND BUFFER 40 characters exclusive of AT prefix Carriage Return and spaces TEST OPTIONS Analog loopback with test pattern Remote digital loopback Digital loopback Test pattern Dial tes...

Page 204: ...R TONE DETECTOR 2200 2300 Hz LOSS OF CARRIER DISCONNECT TIMER 0 7 sec default programmable 0 2 25 5 sec EQUALIZATION Adaptive TRANSMITTER CARRIER FREQUENCIES USR HST 450 bps back channel Originate Mode 375 Hz Answer Mode 1800 Hz USR HST 300 bps back channel Originate Mode 350 Hz Answer Mode 1800 Hz V 32 bis Originate Mode 1800 Hz Answer Mode 1800 Hz Technical Specifications H 5 ...

Page 205: ...Mark 1270 Hz Space 1070 Hz Answer Mode Mark 2225 Hz Space 2025 Hz V 21 Originate Mode Mark 980Hz Space 1180 Hz Answer Mode Mark 1650 Hz Space 1850 Hz RECEIVER CARRIER FREQUENCIES USR HST 450 bps back channel Originate Mode 1800 Hz Answer Mode 375 Hz USR HST 300 bps back channel Originate Mode 1800 Hz Answer Mode 350Hz V 32 bis Originate Mode 1800 Hz Answer Mode 1800 Hz H 6 Technical Specifications...

Page 206: ... Mode 1200 Hz Bell 103 Originate Mode Mark 2225 Hz Space 2025 Hz Answer Mode Mark 1270 Hz Space 1070 Hz V 21 Originate Mode Mark 1650 Hz Space 1850 Hz Answer Mode Mark 980Hz Space 1180 Hz RECEIVE SENSITIVITY 44 dBm 2 dBm TRANSMIT LEVEL 9 dBm maximum COURIER HIGH SPEED MODEMS TRANSMITTER FREQUENCY TOLERANCE 01 Technical Specifications H 7 ...

Page 207: ...COURIER HIGH SPEED MODEMS CERT FICATION FCC Part 68 and Part 15 Class B Domestic DOC Canada UL listed POWER CONSUMPTION 5 watts SIZE 6 25 x 10 25 x 1 5 inches H 8 Technical Specifications ...

Page 208: ...2 C remote access configuration control C 12 E 11 F configure data format C 12 E 12 Pn s password security C 12 E 8 R Rack Controller Unit access 4 18 C 11 T Touch Tone recognition 4 18 C 11 A force answer mode C 1 E 5 A repeat last command 6 8 C 1 A continuous repeat 6 8 C 1 Any key terminate current operation 2 11 6 3 6 9 C 2 AT attention command prefix 2 8 C 1 C 2 B handshake options 4 2 4 3 6 ...

Page 209: ...reen D 8 8 stored phone numbers 8 6 Automatic Repeat Request see ARQ B Back channel 4 2 4 3 H 1 forcing 300 bps S15 B 15 Backspace key ASCII definition SS B 12 Baud rate G 2 Bisync 7 1 G 2 Bits per second bps defined G 2 link negotiation 3 5 4 15 A 1 A 5 online fallback 3 6 A 1 A 4 A 5 rate recognition 4 13 4 15 6 1 E 13 setting the 6 2 Break handling Y 5 11 Break length modem to terminal S21 B 16...

Page 210: ...ation 3 5 4 15 A 1 A 5 online fallback 3 6 A 1 A 4 A 5 H 3 standards compatibility 1 4 1 5 H 1 Data rate select B N 4 13 4 15 Data Set Ready DSR S 4 16 COURIER HIGH SPEED MODEMS Data Terminal Ready DTR DIP switch 1 D 4 17 B 6 DCE 4 1 G 4 Defaults command summary App C NRAM factory B 10 NRAM S Register options B 11 setting 5 1 Department of Communication DOC xi xiii 6 9 Detection phase V 42 A 6 Dia...

Page 211: ...6 4 11 E 19 HST High Speed Technology 3 1 4 2 4 3 6 1 7 4 8 3 A 1 Inactivity timeout S19 1 3 B 16 Indicator lights 2 4 B 4 B 5 F 1 Inquiry I options 8 1 8 5 Installation 2 4 2 6 International calls 6 12 6 13 BO 6 12 G 6 13 P 6 13 V 21 S 27 1 4 B 17 V 23 1 4 B 19 K Kermit protocol 4 4 A 8 L LAPM 1 1 4 5 A 6 Leased line installation operations L E 8 E 10 LED displays 2 4 B 4 B 5 F 1 Line feed ASCII ...

Page 212: ...d sign dialing 6 4 Problems and solutions App D Programming rate switching E 13 E 15 COURIER HIGH SPEED MODEMS Protocol defined G 9 file transfer Kermit etc 4 4 A 8 synchronous 7 1 Pulse dialing 6 4 Q Quiet mode 5 5 D 2 R Rack Controller Unit Access R 4 18 RadioI television interference xii RAM random access memory 8 1 G 9 Rate select commands DTE rate B 4 14 link rate N 4 15 Received data flow co...

Page 213: ...wlett Packard 4 11 E 11 Terminology 4 1 App G Test pattern F 9 Testing App F installation 2 7 2 9 Throughput 4 3 4 4 4 12 A 5 A 9 Touch tones dialing 6 4 timing spacing S11 B 13 recognition T 4 18 Transmission rate 4 4 4 13 4 15 6 1 DTE interface B 3 2 3 4 4 14 link interface N 4 15 Transmit data flow control H 3 2 3 4 4 7 4 8 Trellis coded modulation 1 2 H 1 u Unattended operation see Auto Answer...

Page 214: ...COURIER HIGH SPEED MODEMS NOTES ...

Page 215: ... Service 800 982 5151 Printing 9 8 7 6 5 4 3 2 1 FAX 708 982 0823 ...

Page 216: ...1 015 544 Rev B _ r lll llobotic The Intelligent Choice in Data Communications 8100 North McCormick Blvd Skokie Illinois 60076 2999 Sales 800 DIAL USR FAX 708 982 5235 ...

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