| | AT ImmediateCommands |
| AT | Command line prefix. The Attention Command precedes all other commands listed below except for A/ and the
escape code. For example, the command DT would be typed ATDT |
| A/ | Repeat the previous command (not to be preceded by AT) |
| A | The modem is set to answer mode and goes offhook immediately. |
| Dn | Dial the number immediately following this command where n is the number to be dialed, or that number
combined with other dial subcommands as shown below. Any combination of the subcommands listed below may
be strung together to perform the desired dialing sequence. The number is dialed in the call progress or blind mode depending on register S11 |
| T | Touch Tone Dialing |
| P | Pulse Dialing (Default to Pulse if T or P not used) |
| R | Reverse mode. Puts modem in answer mode immediately after dialing |
| W | Wait for a continuous tone before dialing the next number. Useful for dialing MCI or Sprint. The modem waits for the number of seconds set by the register S7 for the tone to occur. If the tone is not not heard, BUSY or NO DIALTONE result code is issued. |
| @ | Wait for the "quiet answer" - one or more rings followed by 5 seconds of silence - for the length of time defined by register S7 |
| , | Pause the length of time specified by register S8 (default time = 2 seconds). Each comma equals the pause length specified. |
| ! | Flash. This character can be used to go temporarily on-hook in order to get a new dialtone. (Note: Some software uses ! as a carriage return.) |
| ; | Return to the Command state after dialing. This command can only be placed at the end of a dial command. |
| S | Dial a stored number. The numbers are stored in the registers of the microcontroller. |
| S=9 | Dial stored number 0,1,2,or 3 that has been previously stored in non-volatile memory using &Zn command (the non- volatile memory is an optional feature). |
| 0-9 # * ABCD | Digits and -characters that may be use in dialing. il * and ABCD may only be used when tone dialing. |
| Hn | controls the modem on/off hook relay n = 0, on-hook (disconnected) n = 1, off-hook |
| In | Returns product ID/checksum.
n = 0, returns product ID.
n = 1, performs checksum, returns checksum.
n = 2, performs checksum, returns result code.
n = 3, returns ROM part # and revision level |
| On | Puts modem in the online data mode.
n = 0, online
n = 1, online with equalizer retrain sequence (2400 bps only).
Issuing an 'On' command always takes modem offhook |
| Z | Causes a software reset with registers set to default values |
| &F | Sets values for S Registers and commands to factory default |
| &Zn | Stores telephone numbers to optional non-volatile memory. Modem normally comes without non-volatile memory |
| | AT Set Commands |
| Bn | Selects V.22 or Bell 212A in the 1200 bps mode.
*n = 1, Bell 212A with 2225 Hz Answer Back Tone
n = 0, CCITT V.22 with 2100 Hz Answer Back Tone |
| En | Determines whether the modem echoes the data received in the command mode back to the local computer.
*n = 1, echo on |
| Ln | Speaker Volume
*n=2, medium n= 0 or 1, low n = 3, high |
| Mn | Speaker Control
*n = 1, speaker on when dialing until carrier detected
n = 0, speaker off
n = 2, speaker always on
n = 3, speaker on after dialing until carrier detected |
| Qn | Result codes on/off.
*n = 0, codes are sent n = 1, codes are not sent |
| Sr? | Reads the contents of status register r |
| Sr=n | This command may be used to modify an S Register of the modem. It assigns a value n to the status register r. They may be reset to the default value by issuing an '&F' or 'z' command. See next table for @ list of S Registers. |
| Vn | Sets result code format.
*n = 1, words n = 0, numeric |
| Xn | Sets dialing mode, result code format for dial command
*n = 4, Dialtone and busy signal detected. Result
codes 0-7 and 10 enabled.
n = 0, Dialtone and busy signal not recognized (blind
dialing). Result codes 0-4 enabled.
n = 1, Dialtone and busy signal not recognized (blind
dialing). Result codes 0-5 and 10 enabled.
n = 2, Dialtone detected. Busy signal not detected
Result codes 0-6 and 10 enabled.
n = 3, Busy signal detected. Dialtone not detected
Result codes 0-5,7, and 10 enabled. |
| Yn | Long Space Disconnect Option
*n = 0, disabled n = 1, enabled |
| Zn | Recall configuration profile in non-volatile RAM
*n = 0, Recall profile 0 (stored using &WO command)
n = 1, Recall profile 1 (stored using &WI command) |
| &Cn | Enables DCD.
*n = 1, DCD set by modem when remote carrier detected.
n = 0, DCD always on. |
| &Dn | nables DTR. DTR on/off time as specified by S25.
*n = 0, modem ignores DTR.
n = 1, switches to command mode when DTR goes off.
n = 2, same as n = 1. Also hangs up, disables auto
answer.
n = 3, initializes modem when DTR goes off. |
| &Gn | Guard Tone (used only whan in CCITT modes)
*n = 0, noguard tone n = 1, 550Hz n = 2, 1800 Hz
This command need never be used when communicating
over U.S. phone lines. Outside the U.S,, the modem
may need to generate an additional tone, along with
its carrier, to disable echo suppressors in the
central office. This guard tone varies by country. |
| &Mn | Communications Mode
*n = 0, Asynchronous n = 1, n = 2, n = 3, Reserved |
| &Pn | Pulse dial make/break ratio.
*n = 0, 39/61 (for U.S. applications)
n = 1, 33/67 (for foreign applications) |
| &Qn | Communications Mode Option Idle State On-line State
*n = 0 Normal Asynchronous
n = 1 Normal Reserved
n = 2 Dial when DTR = 1 Reserved
Hangup when DTR = 0 Reserved
n = 3 Talk/data, DTR = 0/1 Reserved
|
| &Sn | Controls DSR. DSR ON indicates that the modem is connected to a communication channel and is ready.
*n = 0, DSR is always on
n = 1, DSR turned on at start of handshaking, off in test mode, idle state, or when carrier is lost |
| &Tn | ontrols Test (for n=6,7,8 disabled for 300 bps modes
*n = 0, Ends current test and returns to command mode
n = 1, Initiate local analog loopback
n = 3, Initiate local digital loopback
n = 4. Grant request to remote mode for RDL.
n = 5, Deny request from ramote modem for RDL
n = 6, Initiate ramote digital loopback
n = 7, Initiate remote digital loopback w/ self test
n = 8, Initiate local analog loopback w/ self test |
| | AT Commands for Optional Non-Volatile Memory |
| &V | Displays active configuration profiles (S Register
settings, commands, and telephone numbers. Inputs
from the DTE are ignored while this information is
being sent. |
| @Wn | Store Active Profile. Sends and stores acceptable
values for certain commands and S Registers to non-
volatile RAM. The following may be stored: Commands:Bn,Cn,En,Fn,Ln,Mn,P or T,Qn,Vn,Yn,Xn,&Cn,
&Dn,&Gn,&Jn,&Ln,&Mn,&Pn,&Qn,&Rn,&Sn,&T4,&T5,&Xn
Registers:S0,S14,S18,S21,S22,S23,S25,S26,S27
The last DTE speed and parity are also stored. Stored
values are used on power-up or hard reset.
n = 0, Store active profile in location 0
n = 1, Store active profile in location 1
|
| &Yn | Select Stored Profile on Power Up Option
n = 0, Select profile 0 on power up or hard reset
n = 1, Select profile 1 on power up or hard reset
See the &Wn command for particular commands and S
Registers stored. The selected &Y command survives a
power outage |
| &Zn=x | Store Telephone Number. Stores up to four dialing
strings in non-volatile RAM for later recall using DS
(dial stored number) command. Command format:
&Z <up to 36 characters> <CR>
&Z= <up to 36 characters> <CR>
&Zn <up to 3G characters> <CR> where n=0 to 3
If the delimiter (=) is not present, the characters
following the &Z are treated as telephone numbers
and/or modifiers and are stored in location 0. If the
delimiter is present, th@ characters following it are
stored in the location specified by the character
preceding the delimiter (0 to 3), If not specified, 0
will be used.
Allowable characters: 0 1 2 3 4 5 6 7 8 9 A B C D # *
T P R W @ , ! ;
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