Chapter 2 – AT Commands
Multi-Tech Systems, Inc. AT Commands Reference Guide (S000273G) 5
Chapter 2 – AT Commands

General Commands

Command: AT Attention Code

Values: n/a
Description: The attention code precedes all command lines except A/ and the escape sequence.

Command: Enter Key

Values: na
Description: Press the ENTER or RETURN key to execute most commands.

Command: A Answer

Values: na
Description: Answers an incoming call before the final ring.

Command: A/ Repeat Last Command

Values: n/a
Description: Repeats the last command string. Do not precede this command with AT. Do not press
ENTER to execute.

Command: Bn Communication Standard Setting

Values: n = 0 or 1
Default: 1
Description: B0 Selects ITU-T V.22 mode when the modem is at 300 or 1200 bps.
B1 Selects Bell 212A when the modem is at 300 or 1200 bps.

Command: Ds Dial

Values: s = dial string (phone number and dial modifiers)
Default: none
Description: Dials telephone number s, where s may be up to 40 characters long and include the
following dial string modifiers.
0–9 Digits 0 through 9
* The “star” digit (tone dialing only)
# The “pound” digit (tone dialing only)
A–D A, B, C, D tone digits. Country specific; some countries may prohibit these digits.
L Redials last number. (Must be placed immediately after ATD.)
P Selects pulse-dialing until a T is encountered. Affects current/subsequent dialing.
T Select tone-dialing until a P is encountered. Affects current/subsequent dialing.
W Wait for a new dial tone before continuing to dial.(X2 or X4 must be selected.)
, Pause during dialing for time set in S-Register S8.
; Return to command mode after dialing. (Place at end of dial string.)
! Hook flash. Causes the modem to go quicking on-hook then back off-hook.
@ Wait for silence. Causes the modem to wait for 5 seconds of silence before
processing the next part of the command. If silence is not detected within the
time set in S-Register S7, the modem returns a NO ANSWER or BUSY code.
^ Toggle data calling tone on or off. Applies only to current dialing attempt.
& Detect credit card “bong” tone. If the tone is not detected within the time specified
by S7 (US models), the modem aborts the rest of the sequence and hangs up.
The character should follow the phone number and precede the user’s calling
card number; e.g., ATDT1028806127853500&123456789.