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Text File | 1990-10-17 | 27KB | 654 lines

┌─────────────────────────────────────────────────────────────────┐ │ This Program brought to you through the facilities of │ │ *** SIMPLE SOFTWARE COMPANY *** │ │ P.O BOX 8184 │ │ NEW ORLEANS, LA. 70182 │ │ >>>>>>>> Custom Programming <<<<<<<< │ │ Voice (504) 288-6550 Data (504) 283-9785 │ │ Database - Accounting - Telecommunications - DOS Utilities │ │ Terry Tekippe, Ph.D, Gary M. Raymond, Programmers │ └─────────────────────────────────────────────────────────────────┘ by Gary M. Raymond Here is a summary of technical modem information collected from many sources over the past few years. Hopefully it will serve you as it has helped us. The information lacks great detail but has all the elemental information necessary for code writers. PORT HEX/ADD IBM DEFAULT ISR ADDRESS COM1 3F8 IRQ4 NOTE: AT PC's may address many COM2 2F8 IRQ3 additional serial port COM3 3E8 IRQ4 addresses not mentioned here. COM4 2E8 IRQ3 REGISTER (EXAMPLE: MCR for COM1 = 3F8+4 or 3FC) --------------------------------------------- IER = BASE + 1 ; Interrupt Enable Register IIR = BASE + 2 ; Interrupt Identification Register LCR = BASE + 3 ; Line Control Register MCR = BASE + 4 ; Modem Control Register LSR = BASE + 5 ; Line Status Register MSR = BASE + 6 ; Modem Status Register IER BIT MAPPING --------------------------------------------- BIT Activates Action 0 = Data Received Read RDR 1 = THR empty Output to THR 2 = Data error/break Read LSR 3 = MSR change Read MSR 4 = zero 5 = zero 6 = zero 7 = zero IIR BIT MAPPING --------------------------------------------- BIT 0 = more than 1 intr has occured 1-2 = 00 change in MSR 10 data received 01 THR empty 11 recv error/break 3 = zero 4 = zero 5 = zero 6 = zero 7 = zero LCR BIT MAPPING --------------------------------------------- BIT 0-1 = Data Length 00=5bits 10=7bits 01=6bits 11=8bits 2 = Stop Bits 0=1bit 1=2bits 3-5 = Parity 000=Ignore 101=mark 100=ODD 111=space 110=EVEN 6 = Break Condition 0=disabled 1=enabled 7 = Port Toggle 0=Use THR/RDR/IER 1=Use BRDL/BRDH LSR BIT MAPPING --------------------------------------------- BIT 0 = Set DTR line active 1 = Set RTS line active 2 = USER BIT #1 3 = USER BIT #2 4 = UART loopback 5 = zero 6 = zero 7 = zero LSR BIT MAPPING --------------------------------------------- BIT 0 = byte in RDR (received) 1 = overrun in RDR 2 = Parity error detected 3 = Framing error (out of sync, no stop bit received) 4 = Break Detect 5 = THR empty 6 = TSR empty (removes char from THR) 7 = Time Out MSR BIT MAPPING --------------------------------------------- BIT 0 = change in [C]lear [T]o [S]end CTS 1 = change in [D]ata [S]et [R]eady DSR 2 = change in ring indicator RI 3 = change in [D]ata [C]arrier [D]etect DCD 4 = Clear to send ..... [CTS] set high 5 = Data set ready .... [DSR] set high 6 = Ring Indicator .... [RI] set high 7 = Data Carrier detect [DCD] set high =================================================================== AT ATTENTION COMMAND A/ REPEAT COMMAND A ANSWER MODE COMMAND B/B0 SELECT CCITT V.22 IN 1200 BPS B1 SELECT BELL 212A Dn DIAL COMMAND (n = DIAL STRING, 0-9, *, #, !, W, R, AND, E DISABLE ECHO E1 ENABLE ECHO H ON HOOK (HANG UP) H1 OFF HOOK I/I0 IDENTIFY I1 DISPLAY 000 I2 DISPLAY OK I3 DISPLAY MESSAGE PROGRAM ROM L/L0 LOW VOLUME L1 LOW VOLUME L2 MEDIUM VOLUME L3 MAXIMUM SPEAKER VOLUME M/M0 DISABLE SPEAKER M1 SPEAKER ON UNTIL CARRIER M2 SPEAKER ALWAYS ON M3 DISABLE SPEAKER WHEN DIALING OR CARRIER O GO ON LINE O1 RETRAIN (2400 BPS MODE ONLY) Q/Q0 ENABLE RESULT CODES Q1 DISABLE RESULT CODES Sn=X S REGISTER WRITE (n = VALID S REG, X = ALLOWED VALUE SEE &F COMMAND) Sn? READ SPECIFIED S REGISTER (n = ANY VALID S REGISTER) V0 SELECT DIGIT RESULT CODE V1 SELECT WORD RESULT CODE X0 BLIND DIAL, DISPLAY "CONNECT" X1 BLIND DIAL, DISPLAY "CONNECT 1200/2400" X2 DETECT DIAL TONE, DISPLAY "CONNECT 1200/2400" X3 DETECT BUSY TONE, DISPLAY "CONNECT 1200/2400" X4 DIAL AND BUSY TONE DETECT, DISPLAY "CONNECT 1200/2400" Y0 DISABLE LONG SPACE DISCONNECT Y1 ENABLE LONG SPACE DISCONNECT Z SOFTWARE RESET +++ ESCAPE CODE (GO TO COMMAND MODE IF ON LINE) &C0 DCD ALWAYS ON &C1 DCD FOLLOWS REMOTE CARRIER STATUS &D0 IGNORE DTR &D1 GO TO COMMAND WHEN DTR ON TO OFF &D2 HANGUP AND GO TO COMMAND WHEN DTR ON TO OFF &D3 POWER UP RESET WHEN DTR ON TO OFF &F FETCH FACTORY CONFIGURATION for S REGESTERS &G0 NO GUARD TONE &G1 550 HZ GUARD TONE &G2 1800 HZ GUARD TONE &J0 SELECT RJ-11/RJ-41S/RJ-45S &J1 SELECT RJ-12/RJ-13 &M0 SELECT ASYNCHRONOUS MODE &P0 MAKE BREAK RATIO FOR US (40/60) &P1 MAKE BREAK RATIO FOR FOREIGN STANDARD (33/66) &R0 CTS TRACKS RTS &R1 CTS ON WHEN MODEM READY IN DATA MODE &S0 DSR ALWAYS ON &S1 DSR FOLLOWS RE232 SPECIFICATION &T0 STOP TEST &T1 LOCAL ALB TEST &T3 LOCAL DLB &T ENABLE DLB REQUEST &T5 DISABLE DLB REQUEST &T6 REMOTE DLB &T7 REMOTE DLB AND SELF TEST &T8 LOCAL ALB AND SELF TEST &V VIEW PROFILE S-REG ADDRESS DEFAULT VALID RANGE DESCRIPTION S0 228 0 0-255 RING TO ANSWER ON S1 229 0 0-255 RING COUNT S2 230 43 0-127 ESCAPE CODE CHARACTER S3 231 13 0-127 CR CHARACTER S4 232 10 0-127 LF CHARACTER S5 233 8 0-127 BS CHARACTER S6 234 2 0-255 WAIT FOR DIAL TONE S7 235 30 1-30 WAIT FOR DATA CARRIER S8 236 2 0-255 PAUSE TIME FOR COMMA S9 237 6 1-255(.1SEC) CARRIER DET RESP. TIME S10 238 14 1-255(.1SEC) LOST CARRIER TO HANG UP DELAY S11 239 TOUCH TONE DURATION S12 240 50 0-255 ESCAPE CODE GUARD TIME (1/50SEC) S13 241 NOT USED S14 242 AAH BIT MAPPED OPTION REG S15 243 NOT USED S16 244 0 MODEM TEST OPTIONS S17 245 NOT USED S18 246 0 0-255 TEST TIMER S19 247 NOT USED S20 248 NOT USED S21 249 0 BIT MAPPED OPTIONS REG S22 250 76 BIT MAPPED OPTIONS REG S23 251 7 BIT MAPPED OPTIONS REG S24 252 NOT USED S25 253 5 0-255(.01SEC) DELAY TO DTR (SYNC ONLY) S26 254 1 0-255(.01SEC) RTS TO CTS DELAY (HALF DUP) S27 255 40H BIT MAPPED OPTION REG RESULT CODES DIGIT WORD RESULT 0 OK Command executed without error. 1 CONNECT Carrier detected (300 bbs or 1200 bbs if X0 is set.) 2 RING Phone is ringing (will answer only if auto answer is enabled.) 3 NO CARRIER Carrier lost or never detected. 4 ERROR Error in command line, line too long, or invalid character format. 5 CONNECT 1200 Carrier detected at 1200 bbs if X1 set. 6 NO DIALTONE Displayed if no dialtone is detected within 5 seconds and X2 or X4 is set. 7 BUSY Displayed when a busy signal is detected and Z2 or X4 is set. 8 NO ANSWER Displayed when "@" dial modifier is used and phone continues to ring. 10 CONNECT 2400 Carrier detected at 2400 bbs. X1 or X2 must be set. MODEM BELL 103 BELL 212 V.22 V.22 bis STANDARDS 300 1200 1200 2400 BELL 300 300 300 300** 300** BELL 1200 1200* 1200 1200 1200 CCITT 1200 1200* 1200 1200 1200 CCITT 2400 2400* 1200 1200 2400 CCITT 2400 300* 1200 1200 2400 COMMAND DESCRIPTION AT COMMAND LINE PREFIX (ATTENTION CODE); PRECEDES COMMAND LINES EXCEPT +++ (ESCAPE) AND A/ (REPEAT) COMMANDS. A/ RE-EXECUTE LAST COMMAND LINE; (A/ IS NOT FOLLOWED BY A CARRIAGE RETURN). A OFF-HOOK IN ANSWER MODE. 5 B SELECTS CCITT V.22 OPERATION WHEN COMMUNICATING AT 1200 BPS. B1 (Default) SELECTS BELL 212A OPERATION WHEN COMMUNICATING AT 1200 BPS. D DIAL NUMBER WHICH FOLLOWWD IN THE COMMAND LINE. E MODEM DOES NOT "ECHO" COMMANDS BACK TO TERMINAL. E1 (Default) MODEM SECHOS COMMANDS BACK TO TERMINAL. H (Default) ON-HOOK (HANG-UP) COMMAND. H1 GO OFF-HOOK. I REQUEST PRODUCT IDENTIFICATION CODE. I1 PERFORMS CHECKSUM ON FIRMWARE ROM; RETURNS CHECKSUM. I2 PERFORMS CHECKSUM ON FIRMWARE ROM; RETURNS OK OR ERROR. M SPEAKER OFF. M1 (Default) SPEAKER ON UNTIL CARRIER DETECTED. M2 SPEAKER ALWAYS ON. M3 SPEAKER ON UNTIL CARRIER DETECTED EXCEPT DURING DIALING. O RETURN TO ON-LINE STATE. O1 RETURN TO ON-LINE STATE AND INITIATE RETRAIN. Q (Default) MODEM RETURNS RESULT CODES. Q1 MODEM DOES NOT RETURN RESULT CODES. SRT=N SET REGISTER R TO VALUE N. SR? REQUEST CONTENTS OF REGISTER R. V SHORT FORM NUMERIC RESULT CODES. V1 (Default) FULL WORD RESULT CODES. X 300 BPS COMPATIBILITY MODE; CONNECT RESULT 6 CODE ENABLED. X1 MODEM BLIND DIALS; ALL CONNECT XXXX RESULT CODES ENABLED; BUSY SIGNAL NOT DETECTED. X2 MODEM WAITS FOR DIAL TONE BEFORE DIALING; ALL CONNECT XXXX RESULT CODES ENABLED; MODEM SEND BUSY RESULT CODE IF BUSY DETECTED. X3 MODEM BLIND DIALS; ALL CONNECT XXXX RESULT CODES ENABLED; MODEM SENDS BUSY CODE IF BUSY DETECTED. X4 (Default) MODEM WAITS FOR DIAL TONE BEFORE DIALING; ALL CONNECT XXXX RESULT CODES ENABLED; BUSY SIGNAL DETECTED. Z LOAD STORED CONFIGURATION PROFILE. &C DCD ALWAYS ON. &C1 (Default) DCD ON INDICATES PRESENCE OF DATA CARRIER. &D (Default) MODEM IGNORES DTR. &D1 MODEM ASSUMES COMMAND STATE WHEN ON-TO-OFF TRANSITION DETECTED ON DTR. &D2 MODEM HANGS UP & ASSUMES COMMAND STATE. AUTO ANSWER NOT DISABLED UNLESS EXTERNALLY IMPLEMENTED BY (RI- # DTR-)= A6-. &D3 MODEM ASSUMES INITIALIZATION STATE UPON DETECTING AN ON-TO-OFF TRANSITION ON DTR. &F LOAD FACTORY CONFIGURATION PROFILE. &P (Default) PULSE DIAL MAKE/BREAK RATIO = 39/61 (UK/HK). &P1 PULSE DIAL MAKE/BREAK RATIO = 33/67 (UK/HK). &S DSR ALWAYS ON. &S1 DSR OPERATES IN ACCORDANCE WITH EIA RS-232-C SPEC. &T TERMINATE TEST PROGRESS. &T1 INITIATE LOCAL ANALOG LOOPBACK TEST. &T8 INITIATE LOCAL ANALOG LOOPBACK WITH SELF TEST. &Z STORE TELEPHONE NUMBER. EXPLANATIONS A Go off hook and answer phone immediately. The Model 2400 immediately goes off hook, transmits the answer tone and waits for a carrier from the remote mode. Commands entered after the A command are ignored. A/ Repeat previous command. The last command executed by the Model 2400 will execute again. This command does not require the "AT" prefix or <cr> termination. Bn Bell/CCITT mode select. B0 - Selects CCITT V. 22 operation at 1200 bps. B1 - Selects BELL212A operation at 1200 bps (Default). Most 1200 bps modems in the United States operate using the BELL212A specification. In order to communicate with a modem conforming to the international CCITT V.22 standard, issue the B0 command before dialing. Dn Dial the number immediately following this command where n = digits 0 through 9 together with the dial modifiers listed below. Dial Modifiers: P Pulse dial T Tone dial R Originate call in answer mode W Wait for dial tone before dialing , Pause before dialing next digit ; Return to command mode after dialing @ Wait for quiet answer before dialing ! Flash-hook S Dial the number stores in RAM DIAL MODIFIERS P PULSE DIAL T TONE DIAL , PAUSE ! FLASH @ WAIT FOR SILENCE W WAIT FOR SECOND DIAL TONE ; RETURN TO COMMAND STATE AFTER DIALING R ORIGINATE CALL IN ANSWER MODE D DIAL STORED NUMBER ALL S REGISTER COMMANDS ARE ENTERED IN THE AT COMMAND LINE. EXAMPLE: AT S8=2 S2=43 S7=30 TO READ THE VALUE IN ANY REGISTER USE AT S#? <CR> THE MODEM SHOULD ECHO THE VALUE FOUND IN THE REGISTER # REG Values Register function S0 0 AUTO ANSWER OFF 1-255 AUTO ANSWER ON, ANSWER ON INDICATED # OF RINGS S1 **0-255 RING COUNT (THIS IS A READ-ONLY REGISTER) S2 0-127 ESCAPE CHARACTER NORMALLY SET TO 43 OR "+" 127-255 ESCAPE FUNCTION DISABLED S3 0-127 END OF LINE CHARACTER NORMALLY SET TO 13 (CR) S4 0-127 LINE FEED CHARACTER NORMALLY SET TO 10 (LF) S5 0-127 BACKSPACE CHARACTER NORMALLY SET TO 8 (BS) S6 2-255 SEC PAUSE BEFORE DIALING (NORMALLY 2 SEC) S7 1-255 SEC WAIT FOR CARRIER (NORMALLY SET TO 30 SEC) S8 0-255 SEC PAUSE FOR COMMA IN DIAL STRING (NORMALLY SET TO 2 SEC) S9 1-255 .1SEC CARRIER VALIDATION TIME NORMALLY 6 (.6 SEC) S10 1-255 .1SEC LOSS OF CARRIER DISCONNECT DELAY NORMALLY 14 (1.4 SEC) S11 50-127 .1SEC TOUCH TONE DURATION. THE DEFAULT IS 90. S12 20-255 .02SE ESCAPE SEQENCE PAUSE NORMALLY 50 (1.0 SEC) S13 * POWER UP ASYNC DATA FORMAT (USE CHART BELOW) S14 * OPTION STATUS DEFULT AA (HEX CODE) (USE CHART BELOW) S16 * DEFULT 0. TEST STATUS (USE CHART BELOW) S18 0-255 SEC DEFULT 0. TEST TIMER (REMOTE TEST) S21 * DEFULT 0.OPTION STATUS (USE CHART BELOW) S22 * OPTION STATUS, DEFULT 76. (USE CHART BELOW) S23 * OPTION STATUS NORMALLY 07 (USE CHART BELOW) S25 0-255 SEC DTR DETECT DELAY NORMALLY 5 SEC ASYNC MODE, SYIC AUTO-DIAL AND SYIC MANUAL DIAL MODE .05 SEC S26 0-255 MS RTS TO CTS DELAY (1 MS) S27 * OPTION STATUS, DEFULT 40 (HEX CODE) (USE CHART BELOW) * REGISTERS USED BY MODEM PROCESSOR. DO NOT ALTER THESE * READ ONLY REGISTERS S13 DATA FORMAT: POSITION VALUE FUNCTION BIT 0 - NOT USED BIT 1 - NOT USED BIT 2 0 PARITY OFF 1 PARITY ON BIT 3 0 ODD PARITY 1 EVEN PARITY BIT 4 0 7 DATA BITS 1 8 DATA BITS BIT 5 0 BIT 8=0 1 BIT 8=1 BIT 6 - NOT USED BIT 7 - NOT USED S14 DATA FORMAT: BIT 0 - NOT USED BIT 1 0 LOCAL CHARACTER ECHO OFF 1 LOCAL CHARACTER ECHO ON BIT 2 0 STATUS DISPLAYS ON 1 STATUS DISPLAYS OFF BIT 3 0 STATUS CODES SENT 1 STATUS MESSAGES SENT BIT 4 0 MODEM RESPONDS TO COMMANDS 1 MODEM IGNORES COMMANDS BIT 5 0 TONE-DIALING 1 PULSE-DIALING BIT 6 - NOT USED BIT 7 0 ANSWER MODE 1 ORIGINATE MODE S16 DATA FORMAT: BIT 0 0 ANALOG LOOP OFF 1 ANALOG LOOP ACTIVE BIT 1 - NOT USED BIT 2 0 DIGITAL LOOP OFF 1 DIGITAL LOOP ACTIVE BIT 3 0 REMOTE DIGITAL LOOP REQUESTED BY OTHER MODEM IS OFF 1 REMOTE DIGITAL LOOP REQUESTED BY OTHER MODEM IS ACTIVE BIT 4 0 REMOTE DIGITAL LOOP OFF 1 REMOTE DIGITAL LOOP ACTIVE BIT 5 0 SELF TEST RDL OFF 1 SELF TEST RDL ACTIVE BIT 6 0 SELF TEST ANALOG LOOP OFF 1 SELF TEST ANALOG LOOP ACTIVE BIT 7 - NOT USED S21 DATA FORMAT: BIT 0 0 RJ11/RJ41/45 JACK TYPE 1 RJ12/FJ13 JACK TYPE BIT 1 - NOT USED BIT 2 0 CTS FOLLOWS RTS 1 CTS FORCED ON BIT 3&4 0 MODEM IGNORES DTR 1 MODEM ASSUMES COMMAND STATE WHEN DTR TURNS OFF 2 MODEM ASSUMES COMMAND STATE AND DISABLES AUTO-ANSWER WHEN DTR TURNS OFF 3 MODEM RESETS WHEN DTR TURNS OFF BIT 5 0 DCD FORCED ON 1 DCD FOLLOWS CARRIER BIT 6 0 DSR FORCED ON 1 DSR BEHAVES NORMALLY BIT 7 0 LONG SPACE DISCONNECT DISABLED 1 LONG SPACE DISCONNECT ENABLED S22 DATA FORMAT: BIT 0&1 1 LOW SPEAKER VOLUME 2 MEDIUM SPEAKER VOLUME 3 HIGH SPEAKER VOLUME BIT 2&3 0 SPEAKER ALWAYS OFF 1 SPEAKER ON UNTIL CARRIER DETECTED 2 SPEAKER ALWAYS ON 3 SPEAKER OFF DURING DIALING THEN ON UNTIL CARRIER DETECTED BIT 4&5&6 0 X COMMAND IN EFFECT 4 X 1 COMMAND IN EFFECT 5 X 2 COMMAND IN EFFECT 6 X 3 COMMAND IN EFFECT 7 X 4 COMMAND IN EFFECT BIT 7 0 39/61 MAKE/BREAK RATIO (PULSE DIALING) 1 33/67 MAKE/BREAK RATIO S23 DATA FORMAT: BIT 0 0 REMOTE DIGITAL LOOP REQUEST DENIED 1 REMOTE DIGITAL LOOP REQUEST GRANTED BIT 1&2 0 0-300 BPS 1 600 BPS 2 1200 BPS 3 2400 BPS BIT 3 - NOT USED BIT 4&5 0 EVEN PARITY 1 PARITY BIT ALWAYS 0 2 ODD PARITY 3 PARITY BIT ALWAYS 1 BIT 6&7 0 NO GUARD TONES 1 550 HZ GUARD TONE 2 1800 HZ GUARD TONE S27 DATA FORMAT: BIT 0&1 0 ASYNCRONOUS MODE 1 ASYNC/SYNC MODE 2 SYNC AUTO-DIAL 3 SYNC MANUAL DIAL BIT 2 0 PUBLIC PHONE LINE 1 LEASED LINE BIT 3 - NOT USED BIT 4&5 0 INTERNAL CLOCK USED 1 EXTERNAL CLOCK USED 2 SLAVED CLOCK USED BIT 6 0 CCITT V.22 PROTOCOL (1200 BPS) 1 BELL 212A (1200 BPS) BIT 7 - NOT USED OTHER MODEM COMMANDS: AT STANDARD LEAD IN SEQUENCE (ATTENTION) ATA FORCE ANSWER ATD DIAL (ATD ###-#####) P PULSE (ATDP ###-####) T TONE (ATDT ###-####) ATE1 ENABLE LOCAL CHARACTER ECHO ATE0 DISABLE LOCAL CHARACTER ECHO ATH1 FORCE LINE CONNECT ATH0 FORCE LINE DISCONNECT ATI ECHO VERSION TYPE ATL1 SPEAKER VOLUME LOW ATL2 SPEAKER VOLUME MEDIUM ATL3 SPEAKER VOLUME HIGH ATM0 SPEAKER ALWAYS OFF ATM1 SPEAKER ON EXCEPT WHILE CARRIER PRESENT ATM2 SPEAKER ALWAYS ON ATM3 SPEAKER ON EXCEPT WHILE DIALING AND CARRIER PRESENT ATO GO ONLINE AFTER ESCAPE OR WHILE IN COMMAND MODE ATQ0 STATUS DISPLAY ON ATQ1 STATUS DISPLAY OFF ATV0 STATUS MESSAGES SENT ATV1 STATUS CODES SENT ATX0 "CONNECT" (CODE 1) ALL SPEEDS NO DIAL TONE DETECTION ATX1 "CONNECT" (CODE 1) 0-300 BPS OR "CONNECT 1200" FOR 1200 OR "CONNECT 2400" FOR 2400 BPS NO DIAL TONE DETECTION ATX2 WAIT FOR DIAL TONE (CONNECT SPEEDS SHOWN AS FOR X1) ATX3 DETECT BUSY SIGNAL (CONNECT SPEEDS SHOWS AS FOR X1) ATX4 WAIT FOR DIAL TONE, DETECT BUSY SIGNAL (CONNECT SPEEDS SHOWS AS FOR X1) ATZ RESET TO POWER UP CONDITION (CLEARS ALL REGISTERS) 2400 MODEM SPECIAL COMMANDS: (* = FACTORY SETTING STANDARD) ATB0 CCITT V.22 AT 1200 BPS ATB1 BELL 212A AT 1200 BPS * AT &F RESTORE TO FACTORY C0NFIGURATION AT &G NO GUARD TONE * AT &G1 550 HZ GUARD TONE AT &G2 1800 HZ GUARD TONE AT &J RJ11/RJ41S/RJ45 JACK * AT &J2 RJ12/RJ13 JACK AT &L REGULAR PHONE LINE * AT &L1 LEASED LINE AT &M ASYNC OPERATION * AT &M1 ASYNC/SYNC OPERATION AT &M2 SYNC AUTO DIAL AT &M3 SYNC MANUAL DIAL AT &P 39/61 PULSE MAKE/BREAK RATIO * AT &P1 33/67 PULSE MAKE/BREAK RATIO AT &T4 GRANT RDL TEST REQUEST * AT &T5 DENY RDL TEST REQUEST AT &V VIEW STATUS OF ALL MODEM SETTINGS. SEE ALL S REGISTER SETTINGS AND INTERNAL MODEM COMMAND SETTINGS ON ONE SCREEN! AT &X SYNC CLOCK INTERNAL * AT &X1 SYNC CLOCK EXTERNAL AT &X2 SYNC CLOCK SLAVED AT &Z STORE DIAL COMMAND LINE DATA INTERFACE (2400) AT &C DCD ALWAYS ON AT &C1 DCD ON WHILE CARRIER PRESENT * AT &D DTR IGNORED * AT &D1 DTR FAIL DISCONNECT ENABLED (MODEM RETURNS TO COMMAND MODE) AT &D2 DTR FAIL DISCONNECT ENABLED (MODEM RETURNS TO COMMAND MODE, TURN AUTO ANSWER OFF) AT &D3 DTR FAIL DISCONNECT ENABLED (RESET MODEM) EOF()