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GDI SM2400, User Manual

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GDI SM2400 User Manual Download Page 22

 (&Mn) Async/Sync Mode Selection 
 
&M or &MO (default) selects asynchronous mode. The &Mi, &M2, and &M3 commands 
are reserved for future synchronous mode implementations. They will cause an ERROR 
response from the modem but will not affect operation. 
 
(&Pn) Make/Break Pulse Dial Ratio 
 
The make/break ratio for &P or &PO is 39% make and 61% break, U.S. standard. The 
&P1 command sets the ratio at 33%/67%, compatible with the U.K. and Hong Kong. 
 
(&Rn) RTS/CTS Options (Request to Send/Clear to Send) 
 
The &R or &RO (default) command sets CTS to respond to RTS. CTS will turn ON in 
response to an OFF to ON transition of RTS after a delay specified by S26 (default 10 
mSec). The &R1 command is reserved for future synchronous mode implementation. 
Attempts at &R1 will invoke an ERROR response from the modem but will have no 
effect on operation. 
 
(&Sn) DSR Options (Data Set Ready) 
 
The &S or &SO (default) command causes DSR to remain ON at all times while the 
modem has power. Command &S1 will cause DSR to operate in accordance with CCITT 
V.22 bis/V.22 recommendation. 
 
(&Tn) Test Commands 
 
The &T or &TO command will terminate any test in progress. The &Tn command should 
always be the last command in any given command line. 
The &T1 command will initiate Local Analog Loopback. This is used to verify the path 
which includes the local modem and the local data terminal equipment. S register 18 (test 
timer) or &TO can be used to terminate a test. 
 
Test &T1 example: 
     S18 

is 

the 

test 

duration 

timer 

 
ATS18=O&T1 

Test time of 0 allows the test to run continuously; 
&T1 starts the test. 

 
the quick brown fox jumps...   

User message 

 
+++ 

    Escape 

sequence 

 
OK 

    Modem 

acknowledges 

+++ 

 
AT&T0    Ends 

test 

 
OK 

 

 

 

 

Test complete 

Summary of Contents for SM2400

Page 1: ...MODEL SM2400 2400 BAUD DIAL UP MODEM SMART MODEM USER GUIDE 280 Interstate 80 West Exit 1 PO Box 1330 Verdi NV 89439 Phone 775 345 8000 Fax 775 345 8010 E mail traffi sgdi net ...

Page 2: ...ustody hereof and agrees not to disclose this data or any portion of this data to any unauthorized person without the prior written consent of GDI Communications LLC Recipient further agrees not to incorporate these drawings specifications or technical information in whole or in part in any other product or endeavor THIS LEGEND SHALL BE INCLUDED ON ANY REPRODUCTION OF THIS DOCUMENT ...

Page 3: ...terface It offers 300 1200 2400 baud transmission reception auto dial answer speed detect and Hayes command set compatibility all on a single board with the standard Model 400 form factor In addition to all of the features normally found in a Hayes compatible modem the GDI Model SM2400 is fully temperature tested FEATURES Form factor consistent with the standard Model 400 Front edge mounted status...

Page 4: ...ion 8 Description of Circuit Operation 9 MAINTENANCE 10 Preventive Maintenance 10 Alignments 10 Trouble Analysis 10 Special Considerations 10 Waveforms and Voltage Measurements 10 TEST PROCEDURE 11 COMMAND SET 12 CONFIGURATION S REGISTERS 24 PROGRAMMABLE OPTIONS NOT SAVED IN NVRAM 30 PROGRAMMABLE OPTIONS SAVED IN NVRAM 30 COMMAND SUMMARY 31 ...

Page 5: ... COMPATIBILITY CCITT V 22 bis V 22 A B V 21 Bell 212A and Bell 103 Automatically adapts to calling or called modem ASYNCHRONOUS DATA RATES 2400 and 1200 bps character asynchronous 0 300 bps asynchronous ASYNCHRONOUS CHARACTER FORMAT Character length of 8 9 10 or 11 bits Parity odd even mark space or none ASYNCHRONOUS OVERSPEED UNDERSPEED RANGE Nominal rate 2 5 to 1 25 in character asynchronous mod...

Page 6: ...on in transmitter b Adaptive equalizer for 1200 and 2400 bps in receiver INTERFACE SIGNALS RS232C levels with CCITT V 24 protocols AUTODIALER TYPE DTMF or pulse type dialing specified in commands DTMF TONE PAIR BALANCE Better than 3dB DTMF TONE DURATION AND SPACING Variable from 50 to 255 milliseconds Register S11 Default duration 100 milliseconds PULSE DIALING RATE 10 pulses per second PULSE DIAL...

Page 7: ... CARRIER DETECT Off to On Threshold 43 dBm On to Off Threshold 48 dBm Hysteresis Greater than 2 dB TIMING Request to send Clear to send Delay As per CCITT and BELL protocols during modem handshaking Delay specified by register S26 default 10 mS TIMING DCD ON delay As per CCITT and BELL protocols 600 mS TIMING DCD OFF delay 52 5 12 5 mS at 2400 1200 bps 17 7 mS at 300 bps PERFORMANCE Bit Error Rate...

Page 8: ...ftware expects to talk to the Smart Modem via ACIA1 modem slot and C2 or ACIA2 C20 only If the software communicates with the smart modem via ACIA1 installation consists of simply plugging the modem into the modem slot and connecting the phone line to the modular jack LINE If the softwar talks to the Smart Modem through ACIA2 C20 it is necessary to remove the jumper arrangement plugged into J3 Edg...

Page 9: ...e inadvertently altered restore them to switch 1 ON Switches 2 3 4 OFF Switch 5 BELL CCITT This switch position has been superseded by an enhanced B command It should be left in the OFF condition Switch 6 Dumb Smart If switch 6 is OFF the modem will ignore commands and refrain from sending result codes to the terminal Dumb mode To use the dumb mode first store operating parameters in NVRAM then tu...

Page 10: ...70 Signals the modem that the 170 wants to transmit DCD CF PIN H CD Modem Flags the 170 that a carrier signal is being received GND AB PIN N GND Both Circuit common An off the shelf Hayes modem minimally requires the following additional signal lines to implement full operation for which support from a 170 ACIA is not available NAME DESIGNATION ORIGIN FUNCTION DSR CC Modem Indicates that the modem...

Page 11: ...per impedances to the telephone line while isolating the TIP and RING signals from the analog front end Opto coupler U10 is the isolating element of the ring detector subsection of the DAA Relay K2 allows isolated switching of the phone line between the modem and an optional handset under modem control Relay Ki allows isolated on off hook control and a mechanism for pulse dialing Analog Front End ...

Page 12: ... current consumption on the positive supply making the two a little more symmetrical MAINTENACE Preventive Maintenance This device requires no preventive maintenance Alignments This modem is self aligning using a technique called adaptive equalization Trouble Analysis The G D I Model SM2400 is fully tested over temperature prior to shipment however rare circuit failures do occur for a variety of r...

Page 13: ... on the terminal This enables the Local Analog Loopback mode 3 The modem is now essentially connected to itself Characters typed at the keyboard are sent through modulator and demodulator sections of the modem and returned to the terminal Therefore characters seen at the terminal should be exactly those typed Type a message with many different characters such as the quick brown fox jumps over the ...

Page 14: ...th or without spaces any spaces within or between commands will be ignored by the modem During the entry of any command the delete or backspace key can be used to correct any error Upper case or lower case characters can be used in the commands Some exceptions to this rule are mentioned in association with the specific commands All the commands described in the following paragraphs refer to asynch...

Page 15: ...mitted signal in the originate mode sends scrambled ones at 1200 bps for both V 22 bis and Bell 212A Dstring The Dialing Commands The Dstring command causes the modem to go to the auto dial mode in switched line or to originate a call in leased line The parameters for string include S n stored string digits 0 to 9 touch tones A to D the period and slash P R T comma and semicolon Punctuations paren...

Page 16: ...ait for a dial tone while dialing En Echo Command The Echo command determines whether the modem will echo the characters sent to it while in the command state E1 causes the modem to echo which is the system default and EO sets the modem to no echo Hn Switch Hook Control The H or HO default command will cause the telephone line relay to disconnect hang up The H1 command will cause the telephone lin...

Page 17: ...em will not return result codes S register values identification codes checksum results and results of test modes with self tests are returned Sr Direct Register Commands Sr Returns current decimal value of S register r Sr n Writes the 8 bit binary equivalent of n 0 255 decimal to S register r Modem configuration variables are kept in 8 bit storage elements called S registers Some registers are de...

Page 18: ...e 4 ERROR Invalid Command Line Line Length Exceeds Buffer Size Invalid Character Format Connected at 1200 bps 5 CONNECT 1200 No Dial Tone Received Within Time Out 6 NO DIAL TONE Called Line Busy 7 BUSY No Answer Within Time Out 8 NO ANSWER Connected at 2400 bps 10 CONNECT 2400 Long form results are preceded and terminated with both carriage return and line feed characters Short form codes are only...

Page 19: ...Connect Message Full Message Dialing Waits for Dial Tone Dial Tone Timeout Yes 5 seconds fixed Busy Detection No X3 Connect Message Full Message Dialing Blind Dial Tone Timeout No Busy Detection Yes modem will return BUSY X4 default Connect Message Full Message Dialing Waits for Dial Tone Dial Tone Timeout Yes S6 Busy Detection Yes Yn Enable Long Space Disconnect Y or YO default disables this opti...

Page 20: ... the actual state of the data carrier from the remote modem C1 default causes DCD to reflect remote carrier status Dn DTR Options D or DO causes the modem to ignore DTR After the D1 command the modem will go from data mode to command state on an ON to OFF transition of DTR For D2 default an ON to OFF transition of DTR will cause the modem to go on hook disable auto answer and end in the command st...

Page 21: ...ed off while receiving carrier Speaker volume set to medium Will grant remote digital loopback request Guard tones disabled Minimum DTR pulsewidth is 50 mSec Ring counter set to zero Escape code character 43 Carriage return character 13 carriage return Line feed character 10 line feed Backspace character 08 backspace Wait for dial tone is 2 seconds Wait for carrier after dialing is 30 seconds Dial...

Page 22: ...ts at R1 will invoke an ERROR response from the modem but will have no effect on operation Sn DSR Options Data Set Ready The S or SO default command causes DSR to remain ON at all times while the modem has power Command S1 will cause DSR to operate in accordance with CCITT V 22 bis V 22 recommendation Tn Test Commands The T or TO command will terminate any test in progress The Tn command should al...

Page 23: ...allows the modem to grant a request from the remote modem for a Remote Digital Loopback The command T5 prohibits the local modem from granting a request from a remote modem for a Remote Digital Loopback The command T6 is used to test the local data terminal equipment remote and local modems and the telephone circuit The local modem sends a request for digital loopback message to the remote modem I...

Page 24: ... is applied to the scrambler An error detector capable of identifying errors is connected to the output of the descrambler At the end of the test a three digit error count from 0 to 255 is displayed If the modem is on line when the test starts carrier will be lost This test is useful for checking the local modem transmit and receive circuits Test T8 example ATS18 0 T8 Start test AT T0 End test 000...

Page 25: ... are ignored and need not be included in the count If more than 33 recognized characters are supplied the dial string will be truncated to 33 If the Zn string command is issued in the escape state an ERROR message will be returned and no dial string will be stored If parameter n is omitted 0 is assumed Example 1 AT Z T 555 1212 stores T5551212 into NVRAM location Zero OK modem acknowledges ATDS di...

Page 26: ...g this register to 0 will disable auto answer Setting this register to n non zero will cause the modem to auto answer on the nth ring SI Ring Count S1 is incremented by one each time the modem detects a ring signal S1 is zeroed if no rings occur over any eight second period S2 Escape Code Character This register holds the ASCII decimal value of the escape code character S2 can be set to any value ...

Page 27: ... originate mode extended result code options X3 or X4 allow S7 to establish the time that the modem waits after dialing for the answering modem to go off hook ringback Once the answering modem goes off hook the originating modem then uses S7 to deter mine how long to wait for a carrier before terminating the call This could result in a total wait time dial to connect of up to twice the value in S7...

Page 28: ...e and after the three escape code characters The guard time is in units of 20 mS and has a maximum value of 5 1 seconds 255 20mS Time between the three escape code characters must be less than the guard time in order for the escape sequence to be valid Allowable values for S12 are 20 to 255 If guard time is defined as 0 the timing will not be a factor but the characters must still occur consecutiv...

Page 29: ...l Loop See T6 command 0 Disable Remote Self Test Default 1 Initiate Remote Self Test Digital Test See T7 command 0 Disable Local Self Test Default 1 Enable Local Self Test Analog Test See T8 command Not Used This register not saved in NVRAM S17 Not Used S18 Test Timer If S18 is set from 1 to 255 seconds an Tx command will time out when this time has elapsed automatically ending the test TO will st...

Page 30: ... 4 3 2 1 0 BIT1 BITO See L command 0 0 Undefined 0 1 Low Speaker Volume 1 0 Med Speaker Volume Default 1 1 Hi Speaker Volume BIT3 BIT2 See M command 0 0 Speaker Disabled 0 1 Speaker On Until Carrier Default 1 0 Speaker Always On 1 1 Speaker On Until Carrier but Off During Dial BIT6 BIT5 BIT4 See X command 0 0 0 CONNECT Blind Dial No Busy Detect 0 0 1 Undefined 0 1 0 Undefined 0 1 1 Undefined See X...

Page 31: ...rity Odd 1 1 Parity Mark None BIT7 BIT6 See G command 0 0 No Guard Tone Default 0 1 550 Hz Guard Tone 1 0 1800 Hz Guard Tone 1 1 Undefined S24 Not Used S25 DTR Response Time For DTR option D1 this register specifies the amount of time DTR must be OFF in order to return the modem to command mode For default DO ignore DTR mode this register is disregarded S25 units are tens of milliseconds Default v...

Page 32: ...t for Carrier after Dialing 30 Sec Duration of Pause for the Comma Dial Modifier 2 Sec Carrier Detect Response Time 0 6 Sec Lost Carrier to Hang Up Delay 1 4 Sec Escape Code Guard Time 1 Sec OPTIONS SAVED IN NVRAM W Baud Rate 300 1200 2400 Parity odd even mark space none Answer on nth ring 1 to 255 Auto Answer enable disable Command echo enable disable Result Codes enable disable Result Codes verb...

Page 33: ... L3 Speaker Volume Hi M Speaker off Ml Speaker on until carrier detected M2 Speaker always on M3 Speaker on until carrier detected except when dialing O Return on line O1 Return on line with retrain Q Modem returns result codes Q1 Modem does not return result codes Sr n Set register r to decimal value n Sr Display decimal contents of S register r V Short numeric result codes V1 Full result codes X...

Page 34: ...ulse dial ratio U S P1 Pulse dial ratio U K Hong Kong R CTS follows RTS R1 Ignore RTS CTS always ON S DSR always ON S1 DSR compatible V 24 TO End a test in progress T1 Initiate local analog loopback test T2 Not Used T3 Initiate digital loopback T4 Grants remote digital loopback request T5 Denies remote digital loopback request T6 Initiate remote digital loopback test T7 Initiate remote digital loo...

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