AT Commands
Basic AT Commands
Function
Command
A/
Re-execute command
B0
Select V.22 connect @1200 bps
C1
Return OK message
E0
Turn off command echo
H0
Initiate a hang-up sequence
I0
Report product code
I1
Report pre-computed checksum
I3
Report firmware revision, model,
and interface type
I4
Report response programmed by OEM I5
I6
Report modem data pump model
and code revision
L1
Set low speaker volume
L3
Set high speaker volume
M1
Turn speaker on during handshaking
and turn speaker off while receiving
carrier
N0
Turn off automode detection
N1
Turn on automode detection
O0
Go on-line
P
Force pulse dialing
Q1
Inhibit result codes to DTE
Sn?
Return the value of S-Register n
T
Force DTMF dialing
V0
Report short form result codes
W0
Report DTE speed only
W2
Report DCE speed only
X0
Report basic call progress result codes, X1
i. e., Ok, Connect, Ring, No Carrier
(also, for busy, if enabled, and dial tone
not detected), No Answer and Error
X2
Report basic call progress result codes
and connections speeds, i.e., Ok,
Connect, Ring, No Carrier (also, for
busy, if enabled, and dial tone not
detected), No Answer, Connect XXXX,
and Error
X4
Report all call progress result codes
and connections rate, i.e., Ok, Connect, Y1
Ring, No Carrier, No Answer, Connect
XXXX, Busy, No Dial Tone and Error Z0
Z1
Soft reset and restore stored profile 1
after warm reset
&C1
Allow RLSD to follow the carrier state
&D0
Interpret DTR On-to-OFF transition
per &Qn
&Q0, &Q5, &Q6 The modem ignores DTR
&Q1, &Q4
&Q2, &Q3
&D2
Interpret DTR On-to-OFF transition
per &Qn
&Q0 through &Q6 The modem hangs up
Note: Bold face indicates default value
&F0
Restore factory configuration 0
The modem hangs up
The modem hangs up
Function
Command
A
Go off-hook and attempt to answer a call
B1
Select Bell 212A connect @1200 bps
Dn
Dial modifier
E1
Turn on command echo
H1
If on-hook, go off-hook and enter
command mode
I2
Report "OK" if the calculated checksum
equals the prestored checksum or if the
prestored checksum value is FFh
Report the country code parameter
I7
Report the DAA code
L0
Set low speaker volume
L2
Set medium speaker volume
M0
Turn speaker off
M2
Turn speaker on during handshaking and
while receiving carrier
M3
Turn speaker off during dialing and
receiving carrier and turn speaker on
during answering
O1
Go on-line and initiate a retrain sequence
Q0
Allow result codes to DTE
Sn
Select S-Register n as default
Sn=v
Set default S-Register n to value v
V1
Report long form result codes
W1
Report line speed, EC protocol and DTE
speed
Report basic call progress result codes
and connections speeds (Ok, Connect,
Ring, No Carrier (also, for busy, if
enabled, and dial tone not detected), No
Answer, Connect XXXX, and Error
X3
Report basic call progress result codes
and connections rate, i.e., Ok, Connect,
Ring, No Carrier, No Answer, Connect
XXXX, Busy, and Error
Y0
Disable long space disconnect before on-
hook
Enable long space disconnect before on-
hook
Restore stored profile 0 after warm reset
&C0
Soft reset and force RLSD active
regardless of the carrier state
&D1
Interpret DTR On-to-OFF transition
per &Qn
&Q0, &Q1, &Q4, &Q5, &Q6 Asynchronous escape
&Q2, &Q3
&D1
Interpret DTR On-to-OFF transition
per &Qn
&Q0, &Q1, &Q4, &Q5, &Q6 Soft reset
&Q2, &Q3
&F1
Restore factory configuration 1
The modem hangs up
The modem hangs up