Modem String Reference

Modem String Reference Modem String Reference

AT Commands
Command Values Description
AT n/a The attention code precedes all command lines except A/ and the escape sequence (+++).
ATDs s=dial string with dial modifiers Dial telephone number s where s may be up to 40 characters. Dial string modifiers:
0-9: DTMF digits 0-9
*: The 'star' digit
#: The 'gate' digit
A-D: A-D DTMF digits
L: Redial last number
P: Specify pulse dialing for the following numbers
T: Specify tone dialing for the following numbers
W: Wait for a new dial tone before continuing to dial. (X0, X1, X3, or X4 must be selected)
,: Pause durring dialing for time set in register S8
;: Return to command mode after dialing (must be place at end of string)
!: Hook flash. Causes the modem to go on-hook for one-half second and then off-hook again.

ATEn n=0 or 1 E0: Do not echo keyboard character to the computer
E1: Do echo keyboard characters to the computer.
ATHn n=0 or 1 H0: Go on-hook to hang up
H1: Go off-hook to make the phone line busy.
ATIn n=0-7 I0: Display product code
I1: Calculate and display ROM checksum
I2: Calculate ROM checksum and display it to the prestored checksum
I3: Display the firmware version and application codes
I4: Display OEM defined identifier string in either binary or ASCII format
I5: Display country code
I6: Display modem data pump model and internal code version
I7: Display the DAA code resulting from MCU interrogation of the DAA for auto DAA recognition
ATLn n=0,1,2, or 3 L0: Select low volume
L1: Select low volume
L2: Select medium volume
L3: Select high volume
ATMn n=0,1,2, or 3 M0: Speaker always off
M1: Speaker on until carrier signal detected
M2: Speaker always on when modem is off-hook
M3: Speaker on until carrier is detected, except while dialing
ATNn n=0 or 1 N0: Disables automatic modulation negotation; uses connection speed specified in S37
N1: Enables automatic modulation negotation
ATSr=n r=S-register number; n varies Set valuse of Sr to n
ATVn n=0 or 1 V0: Display result codes as digits
V1: Display result codes as words
ATWn n=0, 1, or 2 W0: Modem reports DTE speed only
W1: Modem reports the line speed, the error correction protocol, and the DTE speed
W2: Modem reports DCE speed only
ATXn n=0-4 X0: Sends OK, CONNECT, RING, NO CARRIER, ERROR, and NO ANSWER
X1: Sends X0 messages and CONNECT speed
X2: Sends X1 messages with NO DIALTONE
X3: Sends X1 messages with BUSY
X4: Sends all responses
ATYn n=0 or 1 Y0: Disable sending or responding to long space bread signal on disconnect
Y1: Enable long space detect
ATZ none Reset modem
AT&Cn n=0 or 1 &C0: Ignores the state of carrier on remote modem and DCD circuit is always on
&C1: DCD turns on when the remote modem's carrier signal is detected
AT&Dn n=0, 1, 2, or 3 &D0: DTR is ignored
&D1: If DTR drops modem drops to command mode and remains connected
&D2: If DTR drops modem hangs up
&D3: If DTR drops modem hangs up and resets itself
AT&Fn n=0 or 1 &F0: Restore factory default setting 0
&F1: Restore factory default setting 1

AT&Gn n=0, 1, or 2 &G0: Disable guard tone
&G1: Enable 550 Hz guard tone
&G2: Enable 1800 Hz guard tone
AT&Kn n=0, 3-6 &K0: Flow control disabled
&K3: Enable CTS/RTS hardware flow control
&K4: Exable XON/XOFF flow control
&K5: Enable transparent XON/XOFF flow control
&K6: Enable both CTS/RTS and XON/XOFF flow control
AT&Qn n=0, 5, or 6 &Q0: Asynchronous with no data buffering and no error correction
&Q5: Asynchronous with data buffering and error correction
&Q6: Asynchronous with data buffering and no error correction
AT&Sn n=0 or 1 &S0: Force DSR ON at all times
&S1: DSR becomes active ater answer tone is detected

AT&Vn n=0 or 1 &V0: Displays the active modem settings
&V1: Displays the last connection statistics
AT&Wn n=0 or 1 &W0: Store active modem string in NVRAM as profile 0
&W1: Store active modem string in NVRAM as profile 1
AT%En n=0, 1, or 2 %E0: Disable line quality monitor and auto-retrain
%E1: Enable line quality monitor and auto-retrain
%E2: Enable line quality monitor and fallback/fall forwared
AT%L none Return line signal level
AT%Q none Report line signal quality
AT%Cn n=0, 1, 2, 3 %C0: Disable data compression
%C1: Enables MNP 5 data compression
%C2: Enables V.42bis data compression
%C3: Enables both V.42bis and MNP 5 data compression
AT\Nn n=0-5 Error correction mode selection
\N0: Non-error correction mode with data buffering
\N1: Direct mode
\N2: V.42/MNP reliable mode
\N3: Same as \N2
\N4: V.42 reliable mode
\N5: MNP reliable mode
AT\Vn n=0 or 1 Enable/Disable Single Line Connect Message
\V0: disable
\V1: enable
Format for message is: CONNECT, DTE, speed, modulation, protocol, compression, line speed
+MS none Selects modulation, enables/diables automode, and sets line speed parameters.
+MS=mod[,[automode][,[min_rate],[max_rate]]]
+MS=? will report valid modulation settings
+++ none Escape Sequence, will put modem in command mode

AT Commands
Command	Values	Description
AT	n/a	The attention code precedes all command lines except A/ and the escape sequence (+++).
ATDs	s=dial string with dial modifiers	Dial telephone number s where s may be up to 40 characters. Dial string modifiers: 0-9: DTMF digits 0-9 *: The 'star' digit #: The 'gate' digit A-D: A-D DTMF digits L: Redial last number P: Specify pulse dialing for the following numbers T: Specify tone dialing for the following numbers W: Wait for a new dial tone before continuing to dial. (X0, X1, X3, or X4 must be selected) ,: Pause durring dialing for time set in register S8 ;: Return to command mode after dialing (must be place at end of string) !: Hook flash. Causes the modem to go on-hook for one-half second and then off-hook again.
ATEn	n=0 or 1	E0: Do not echo keyboard character to the computer E1: Do echo keyboard characters to the computer.
ATHn	n=0 or 1	H0: Go on-hook to hang up H1: Go off-hook to make the phone line busy.
ATIn	n=0-7	I0: Display product code I1: Calculate and display ROM checksum I2: Calculate ROM checksum and display it to the prestored checksum I3: Display the firmware version and application codes I4: Display OEM defined identifier string in either binary or ASCII format I5: Display country code I6: Display modem data pump model and internal code version I7: Display the DAA code resulting from MCU interrogation of the DAA for auto DAA recognition
ATLn	n=0,1,2, or 3	L0: Select low volume L1: Select low volume L2: Select medium volume L3: Select high volume
ATMn	n=0,1,2, or 3	M0: Speaker always off M1: Speaker on until carrier signal detected M2: Speaker always on when modem is off-hook M3: Speaker on until carrier is detected, except while dialing
ATNn	n=0 or 1	N0: Disables automatic modulation negotation; uses connection speed specified in S37 N1: Enables automatic modulation negotation
ATSr=n	r=S-register number; n varies	Set valuse of Sr to n
ATVn	n=0 or 1	V0: Display result codes as digits V1: Display result codes as words
ATWn	n=0, 1, or 2	W0: Modem reports DTE speed only W1: Modem reports the line speed, the error correction protocol, and the DTE speed W2: Modem reports DCE speed only
ATXn	n=0-4	X0: Sends OK, CONNECT, RING, NO CARRIER, ERROR, and NO ANSWER X1: Sends X0 messages and CONNECT speed X2: Sends X1 messages with NO DIALTONE X3: Sends X1 messages with BUSY X4: Sends all responses
ATYn	n=0 or 1	Y0: Disable sending or responding to long space bread signal on disconnect Y1: Enable long space detect
ATZ	none	Reset modem
AT&Cn	n=0 or 1	&C0: Ignores the state of carrier on remote modem and DCD circuit is always on &C1: DCD turns on when the remote modem's carrier signal is detected
AT&Dn	n=0, 1, 2, or 3	&D0: DTR is ignored &D1: If DTR drops modem drops to command mode and remains connected &D2: If DTR drops modem hangs up &D3: If DTR drops modem hangs up and resets itself
AT&Fn	n=0 or 1	&F0: Restore factory default setting 0 &F1: Restore factory default setting 1
AT&Gn	n=0, 1, or 2	&G0: Disable guard tone &G1: Enable 550 Hz guard tone &G2: Enable 1800 Hz guard tone
AT&Kn	n=0, 3-6	&K0: Flow control disabled &K3: Enable CTS/RTS hardware flow control &K4: Exable XON/XOFF flow control &K5: Enable transparent XON/XOFF flow control &K6: Enable both CTS/RTS and XON/XOFF flow control
AT&Qn	n=0, 5, or 6	&Q0: Asynchronous with no data buffering and no error correction &Q5: Asynchronous with data buffering and error correction &Q6: Asynchronous with data buffering and no error correction
AT&Sn	n=0 or 1	&S0: Force DSR ON at all times &S1: DSR becomes active ater answer tone is detected
AT&Vn	n=0 or 1	&V0: Displays the active modem settings &V1: Displays the last connection statistics
AT&Wn	n=0 or 1	&W0: Store active modem string in NVRAM as profile 0 &W1: Store active modem string in NVRAM as profile 1
AT%En	n=0, 1, or 2	%E0: Disable line quality monitor and auto-retrain %E1: Enable line quality monitor and auto-retrain %E2: Enable line quality monitor and fallback/fall forwared
AT%L	none	Return line signal level
AT%Q	none	Report line signal quality
AT%Cn	n=0, 1, 2, 3	%C0: Disable data compression %C1: Enables MNP 5 data compression %C2: Enables V.42bis data compression %C3: Enables both V.42bis and MNP 5 data compression
AT\Nn	n=0-5	Error correction mode selection \N0: Non-error correction mode with data buffering \N1: Direct mode \N2: V.42/MNP reliable mode \N3: Same as \N2 \N4: V.42 reliable mode \N5: MNP reliable mode
AT\Vn	n=0 or 1	Enable/Disable Single Line Connect Message \V0: disable \V1: enable Format for message is: CONNECT, DTE, speed, modulation, protocol, compression, line speed
+MS	none	Selects modulation, enables/diables automode, and sets line speed parameters. +MS=mod[,[automode][,[min_rate],[max_rate]]] +MS=? will report valid modulation settings
+++	none	Escape Sequence, will put modem in command mode

**NOTE**
This is only a partial list which has been compliled of the most useful commands. For a more detailed list of the Hayes AT Modem Command Set, click here!