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Appendix B
AT Commands
To summarize AT command syntax:
Multiple commands can be strung together in one line.
Command lines cannot exceed 40 upper- or lower-case characters. (Do not mix upper- and lower-case.) The faxmodem ignores space and hyphen characters.
Command lines must start with AT and end with a carriage return (Return or Enter).
A missing command parameter is assumed to be a zero. For example, ATH is the same as ATHO.
4/ on a line by itself without a carriage return causes the faxmodem to repeat the previous command.
To switch to terminal mode from data mode, wait at least one second, type + + + (the default escape characters), and wait at least one second before entering other characters. After the OK message from the modem, you can enter AT commands. To return to data mode, type ATO and press Return (or Enter).
Bold indicates the default setting. (Not all commands have defaults.)
Command Function
| A | Answers incoming call immediately |
| B0 B1 |
Uses V.22 connection at 1200 bps Uses Bell 212A connection at 1200 |
| Dn | Dials telephone number n You can combine D with one or more of the following modifiers: L Redials last numberP Uses pulse dialing T Uses tone dialing W Waits for dial tone , Pauses during dial as specified in register S8 (default: 2 sec) @ Waits for at least 5 seconds of silence R Command accepted but not acted upon. ; Returns to command mode after dialing (put after dial string) ! Goes on hook (time specified in S29) S=(0-3) Dial one of 4 numbers stored with &Zn ^ Turn on calling tone (data only) |
| E0 E1 |
Command characters not echoed Command characters echoed |
| H0 H1 |
Forces faxmodem to hang up Forces faxmodem off-hook |
| I0 I1 I2 I3 |
Returns 3-digit product code Returns ROM checksum Computes checksum, compares with value in ROM. and returns OK or ERROR Returns firmware revision code Returns faxmodem identifier string Returns country code Returns data pump model and revision code |
| L0 L1 L2 L3 |
Lowest speaker volume Low speaker volume Medium speaker volume Highest speaker volume |
| M0 M1 M2 M3 |
Speaker always off Speaker on until carrier detected Speaker always on Speaker on |
| N0
|
Disables auto-mode (automatic modulation negotiation) uses connection
speed specified in S37. (Equivalent to +MS <automode> set to O.) Enables auto-mode (Equivalent to +MS <automode> set to 1) |
| O0 O1 |
Enters data mode Enters data mode and retrains faxmodem to phone line conditions |
| P | Pulse dialing until T command. |
| Q0 Q1 |
Enables responses to computer (DTE) Disables responses to computer |
| Sn Sn=v Sn? |
Establishes S-register n as the default register Sets register n to value v Returns the value of register n |
| T | Tone dialing until P command |
| V0 V1 |
Send numeric (short form) responses Send word (long form) responses |
| W0 W1 W2 |
Reports DTE (computer-to-modem) speed only Reports DCE (modem-to-modem) speed. error correction protocol, and DTE speed Reports DCE (modem-to-modem) speed only |
| X0 X1 X2 X3 X4 |
Sends OK. CONNET. RING. NO CARRIER. ERROR. and NO ANSWER. Sends XO messages and CONNECT speed Sends X1 messages and NO DIALTONE. Sends X2 messages and BUSY Sends all responses |
| Y0 Y1 |
Disables long space disconnect Enables lone space disconnect: with error correction. hangs up after 1.6 second signal break: without error correction, sends 4second space before hanging up. |
| Z0 Z1 |
Resets faxmodem to profile O. (See &WO.) Resets faxmodem to profile 1. (See &W1.) |
| &C0 &C1 |
Forces RLSD (DCD) on RLSD (DCD) follows remote carrier |
| &D0 &D1 &D2 |
DTR is assumed on. Allows operation with DTEs that do not provide DTR
signal. Modem interprets DTR drop as if escape sequence was received. Returns to terminal mode without disconnecting. DTR drop causes modem to hang up. Auto-answer is inhibited. DTR drop causes modem to do soft reset. &Y setting determines which profile is loaded. |
| &F | Loads factory profile |
| &G0 &G1 &G2 |
Disables guard tone Disables guard tone Enables 1800 Hz guard tone |
| &K0 &K3 &K4 |
Disables flow control Enables RTS/CTS (hardware) flow control Enables XON/XOFF flow control |
| &M0 | Selects direct asynchronous mode |
| &P0 &P1 &P2 &P3 |
Make/break dial ratio of 39/61 at 10 pps Command accepted, but not acted upon. Command accepted, but not acted upon Command accepted, but not acted upon |
| &Q0 &Q5 &Q6 |
Selects direct asynchronous mode (no error correction or speed buffering) Faxmodem negotiates error-correcting connection Selects asynchronous mode with speed buffering (no error correction |
| &S0 &S1 |
Forces Data Set Ready (DSR) on continuously DSR active after answer tone detected and inactive after carrier loss |
| &V | Displays current and stored profiles, and stored numbers |
| &W0 &W1 |
Saves active configuration as profile O Saves active configuration as profile 1 |
| &Y0 &Y1 |
Faxmodem uses profile O on powerup. (See &WO.) Faxmodem uses profile 1 on powerup. (See &W1.) |
| &Zn=x | Stores telephone number (up to 34 digits) in non-volatile memory location
n (0-3) |
| %C0 %C1 %C2 %C3 |
Disable data compression Enable MNPS compression Enable V.42bis compression Enables both MNPS and V.42bis |
| %E0 %E1 %E2 %E3 |
Disables line-quality monitoring and auto-retraining Enables monitoring and retraining Enables monitoring and fallback/fall forward Enables monitoring, retraining, and fast |
| %L | Reports received signal level in -dbm |
| %Q | Reports line signal quality |
| \A0 \A1 \A2 \A3 |
64-character maximum MNP block size 128-character maximum MNP block size 192-character maximum MNP block size 256-character maximum MNP block size |
| \Bn | In non-error correction mode. transmits line break to remotemodem in 100
ms units (1-9 with 3 as default) |
| \G0 \G1 |
Disables XON/XOFF (modem-to-modem) flow control Enables XON/XOFF (modem-to-modem) flow control |
| \Kn | Defines break type |
| \L0 \L1 |
Uses stream mode for MNP connection Uses interactive block mode for MNP connection |
| \N0 \N1 \N2 \N3 \N4 \N5 |
Normal data link with speed buffering; no error correction Selects serial interface; same as &Q0 Selects reliable (error correction) mode Selects auto-reliable mode LAPM error correction only MNP error correction only |
| )M0 )M1 |
Disables MNP10 EC link negotiation power adjustment (cellular) Enables MNP10 EC link negotiation power adjustment (cellular) |
| *H0 *H1 *H2 |
Link negotiation between two MNP1O EC modems occurs at highest supported
rate. Link negotiation between two MNP10 EC modems occurs at 1200 bps (for cellular connections) Link negotiation between two MNP10 EC modems occurs at 4800 bps (for low-quality phone lines) |
| -K0 -K1 -K2 |
Disables V.42 LAPM to MNP10 EC conversion Enables V.42 LAPM to MNP1O EC conversion Enables V.42 LAPM to MNP10 EC conversion: inhibits MNP Extended Services initiation during V.42 LAPM answer mode detection |
| -Q0 -Q1 |
Disables MNP 10 EC fallback to 2400 bps Enables MNP 10 EC fallback to 2400 bps |
| @Mn @M0 @M1 @M2-@M10 @M11 @M12 to 31 |
Sets initial transmit power level (cellular) to: -26 dBm -30 dBm -10 dBm -11 dBm -12 dBm to -31 dBm |
| :E0 :E1 |
Disables V.32 compromise equalizer Enables V.32 compromise equalizer |
+MS=<mod>[,[ <automode>], <min_rate>], <max_rate>]]]] See NOTE.
Selects modulation: optionally enables or disables automatic modulation negotiation with the remote modem or faxmodem:
optionally sets minimum and/or maximum rates
<mod> Selects modulation: Possible Rates (bps): 0 V.21 300 1 V.22 1200 2 V.22 bis 2400, 1200 3 V.23 1200 9 V.32 9600, 4800 10 V.32 bis 14400, 12000, 9600, 7200, 4800 11 V.34 28800, 26400, 24000, 19200. 16800, 14400, 12000, 9600, 7200, 4800, 2400 64 Bell 103 300 69 Bell 212 1200 74 V.FC 28800, 26400, 24000, 21600, 19200, 16800, 14400
[,[<auto-mode>]
0
1
Enables or disables automatic modulation negotiation with the remote modem.
Disables (Equivalent to NO command.)
Enables (Equivalent to N1 command.)[,]<min-rate>] See "Possible Rates (bps) above. Default: 300 bps
[,[<max-rate>] See "Possible Rates (bps) above. Default: 28800 bps
NOTE Use a comma (,) to separate optional subparameters. For example:
+MS=11,1,300,28800 (+MS command with the default settings). subparameters that you do not enter remain at their current value. (Type a comma only to skip a subparameter or carriage return to skip the last subparameter) For example: +MS=.0. <Enter> disables auto mode and keeps all other settings al their current value.
