Basic Hayes AT command set

Below you find a list of basic Hayes commands. It is the basic AT command set supported on virtually any modem device. Click on a single command to read more information.

Command Description
, Pause
+++ Escape Sequence
A Answer Mode
A/ Repeat Sequence
AT Attention!
B0 Select Communication Protocol: ITU-T v.22 (300bps or 1200bps)
B1 Select Communication Protocol: Bell 212A (300bps or 1200bps)
B2 Select Communication Protocol: Enables v.23
C0 Transmit carrier disabled
C1 Transmit carrier enabled
D! Enable "flash"
D"555-4NET" D"555-4NET"
D, Pause before dial
D@ Modem will wait for a quiet answer before dialing the rest of the dial string
DL Redial the last dialed number
DP Pulse dial
DR Enable answer mode
DS=x Dial the stored telephone number in x
DT Tone dial
DW Resume dialing after dial tone is detected
E0 Echo Disabled
E1 Echo Enabled
F0 Preset the line speed to: Auto mode
F1 Preset the line speed to: V.21 300bps
F10 Preset the line speed to: V.32bis 14,400bps
F2 Reserved
F3 Preset the line speed to: V.23 75Tx/1200Rx with AT%F1 / V.23 1200Tx/75Rx with AT%F2
F4 Preset the line speed to: V.22 1,200bps
F5 Preset the line speed to: V.22bis 2,400bps
F6 Preset the line speed to: V.32bis 4,800bps
F7 Preset the line speed to: V.32bis 7,200bps
F8 Preset the line speed to: V.32bis 9,600bps
F9 Preset the line speed to: V.32bis 12,000bps
H0 Hook Select: On-hook
H1 Hook Select: Off-hook
I0 Report Modem Information: Modem model and speed
I1 Report Modem Information: ROM checksum
I10 Report Modem Information:
I11 Report Modem Information:
I12 Report Modem Information:
I13 Report Modem Information:
I14 Report Modem Information:
I15 Report Modem Information:
I16 Report Modem Information:
I17 Report Modem Information:
I18 Report Modem Information:
I2 Report Modem Information: Tests ROM checksum THEN reports it
I3 Report Modem Information: Firmware revision level.
I4 Report Modem Information: Data connection info
I5 Report Modem Information: Regional Settings
I6 Report Modem Information: Data connection info
I7 Report Modem Information: Manufacturer and model info
I8 Report Modem Information:
I9 Report Modem Information:
L0 Set Speaker Volume: Mute
L1 Set Speaker Volume: Low volume
L2 Set Speaker Volume: Medium volume
L3 Set Speaker Volume: High volume
M0 Set Speaker Mode: Disable speaker
M1 Set Speaker Mode: Enable speaker until a carrier signal is detected
M2 Set Speaker Mode: Enable speaker
M3 Set Speaker Mode: Enable speaker after dialing but disable after a carrier signal is detected
N0 Automode selection/detection: Disable automode
N1 Automode selection/detection: Enable automode
N2 Automode selection/detection: Enable automode
N3 Automode selection/detection: Enable automode
N4 Automode selection/detection: Enable automode
N5 Automode selection/detection: Enable automode
O0 Retraining disabled in on-line command mode
O1 Retraining enabled in on-line command mode
P Pulse Dialing
Q0 Enable result codes to DTE
Q1 Disable result codes to DTE
Sn Status Registers
T Tone Dialing
V0 Format of Result Code:
V1 Format of Result Code:
W0 Extended Result Codes: Enables the CONNECT result codes to report the DTE speed.
W1 Extended Result Codes: Enables the CONNECT result codes to report the DTE speed.
W2 Extended Result Codes: Enables the CONNECT result codes to report the DCE speed.
X0 Result Codes for Call Progress: Disable busy and dialtone detection. Result codes 0-4 enabled.
X1 Result Codes for Call Progress: Disable busy and dialtone detection. Result codes 0-5,10 enabled.
X2 Result Codes for Call Progress: Disable busy detection, enable dialtone detection. Result codes 0-6,10 enabled.
X3 Result Codes for Call Progress: Enable busy detection, disable dialtone detection. Result codes 0-5,7,10 enabled.
X4 Result Codes for Call Progress: Busy and dialtone detection enabled. Result codes 0-7,10 enabled.
Y0 Long Space Disconnect: Long space disconnect disabled
Y1 Long Space Disconnect: Long space disconnect enabled
Z0 Soft Reset and Restore: Restore setting 0
Z1 Soft Reset and Restore: Restore setting 1