98
Appendix
Appendix E

AT Command Summary

Command Values Description

AT
n/a Attention Code
The attention code precedes all command lines except
A/
,
A:
and escape codes.
RETURN
n/a RETURN Key
Press the RETURN (ENTER) key to execute most commands.
A
n/a Force Answer Mode
Answer call immediately without waiting for ring.
A/
n/a Repeat Last Command
Do not precede this command with AT. Do not press RETURN to execute.
A:
n/a Continuous Redial
Continuous redial of last number until answered. (10 redials in North American models.
Not used on International or U.K. models.)
&An
n = 0 or 1 Answerback
*** &A0 Answerback off.
&A1 Answerback on.
$An
n = 0 or 1 Auto-Reliable Buffering
*** $A0 Discard data received during establishment of reliable connection
$A1 Buffer data received during establishment of reliable connection
#An
n = 0–3 Auto Speed Detection in Answer Mode
*** #A0 Start at maximum speed and fall back to 14400 to 12000 to 9600 to 4800 to
2400 to 1200 to 300 bps.
#A1 Maximum speed only.
#A2 Start at maximum speed and fall back incrementally to 4800 bps only.
#A3 Start at 2400 bps and fall back to 1200 to 300 bps only.
Bn n
= 0 or 1 Answer Tone (International models only)
*** B0 Select ITU-T V.21 answer tone.
B1 Select Bell 103 answer tone.
&BSn n
= 0 or 1 Maximum Reliable Block Size
&BS0 Maximum transmit block size of 64 characters.
*** &BS1 Maximum transmit block size of 256 characters.
$BAn n
= 0 or 1 Baud Adjust
*** $BA0 Set baud adjust off, speed conversion on. (Serial port speed is independent of
modem data rate.)
$BA1 Set baud adjust on, speed conversion off. (Serial port speed is same as
modem data rate.)
&Cn n
= 0, 1, 2, Carrier Detect Control
or 4 &C0 Force Carrier Detect on.
*** &C1 Let Carrier Detect follow carrier signal.
&C2 Let Carrier Detect drop for time set by
S24
on disconnect, then go high again.
&C4 Reset modem when Carrier Detect drops.