AUTO-RETRAIN - FALLBACK/FALLFORWARD
Type:	Configuration
Format:	AT [cmds] %En [cmds]
Example:	AT %E1 <CR>
Description:	Controls auto-retrain mode and fallback/fall forward.
Command	Function
%E0	Auto-retrain disabled.
%E1	Auto-retrain enabled.
%E2	Fallback/fall forward enabled.

BIT-MAPPED REGISTER S14
Format		AT [cmds] S14=n [cmds]
Example:		ATS14=138<CR>
Default:		138
Range:		0-174
Unit:		Bit-mapped
Description:		Controls echo, result codes, result code display, dial mode, and answer/originate mode.
Bit	Value		Function
0	0		Not used.
1	0 » 1		Command echo disabled. Command echo enabled.
2	» 0 1		Result codes enabled. Result codes disabled.
3	0 » 1		Display result codes in numeric format. Display result codes in verbose format.
4	0		Not used.
5	» 0 1		Tone dial enabled. Pulse dial enabled.
6	0		Not used.
7	0 » 1		Answer mode enabled. Originate mode enabled.

BIT-MAPPED REGISTER S21
Format		AT [cmds] S21=n [cmds]
Example:		ATS21=4<CR>
Default:		4
Range:		0-253
Unit:		Bit-mapped
Description:		Selects jack type, CTS signal, low DTR action, DCD signal, DSR signal, and the Long Space Disconnect function.
Bit	Value		Function
0	» 0 1		Selects RJ-11 jack. Selects RJ-12 or RJ-13 jack.
1	0		Not used.
2	0 » 1		CTS forced high. CTS follows RTS.
4, 3	» 00 01 10 11		DTR signal ignored. Modem goes to command mode on low DTR. Modem disconnects on low DTR. Auto-Answer is disabled. Modem is initialized on low DTR.
5	» 0 1		DCD forced high. DCD normal.
6	» 0 1		DSR forced high. DSR normal.
7	» 0 1		Long Space Disconnect function disabled. Long Space Disconnect function enabled.

BIT-MAPPED REGISTER S22
Format		AT [cmds] S22=n [cmds]
Example:		ATS22=117<CR>
Default:		117
Range:		0-127
Unit:		Bit-mapped
Description:		Controls speaker volume and controls, and limits results codes.
Bit	Value		Function
1, 0	00 » 01 10 11		Off volume. On volume. Medium level volume. High level volume.
3, 2	00 » 01 10 11		Speaker off. Speaker off on carrier. Speaker always on. Speaker on during handshake.
6, 5, 4	000 » 100 101 110 111		Basic result codes only enabled. Basic and connection speed result codes enabled. Basic and connection speed result codes and dialtone detection enabled. All result codes except dialtone detection enabled. All result codes enabled.

BIT-MAPPED REGISTER S23
Format		AT [cmds] S23=n [cmds]
Example:		ATS23=55<CR>
Default:		55
Range:		0-189
Unit:		Bit-mapped
Description:		Grants/denies remote digital loopback, controls DTE rate and parity, and sets guard tone.
Bit	Value		Function
0	0 » 1		Remote digital loopback denied. Remote digital loopback allowed.
3, 2, 1	000 001 010 » 011 100 101 110		Sets serial port speed to 0-300bps. Sets serial port speed to 600bps. Sets serial port speed to 1200bps. Sets serial port speed to 2400bps. Sets serial port speed to 4800bps. Sets serial port speed to 9600bps. Sets serial port speed to 19200bps.
5,4	00 01 10 » 11		Parity even. Not used. Parity odd. No Parity.
7, 6	» 00 01 10		Guard tone disabled. Guard tone 550Hz enabled. Guard tone 1800Hz enabled.

BIT-MAPPED REGISTER S27
Format		AT [cmds] S27=n [cmds]
Example:		AT S27=73 <CR>
Default:		73
Range:		0 - 110
Unit:		Bit-mapped
Description:		Selects sync/async mode, line type, internal clock, and ITU-T/Bell modes.
Bit	Value		Function
3, 1, 0	000 001 010 011 100 » 101 110		Asynchronous mode, serial port speed follows connect speed. Asynchronous command mode and synchronous connect mode. Asynchronous command mode and synchronous connect mode, DTR dialing enabled. Asynchronous command mode on low DTR, synchronous connect mode on high DTR. Hayes AutoSync™ mode - serial port locked at 9600bps. Error correcting mode. Asynchronous operation in normal mode.
2	» 0 1		Dial up line. Leased line.
5, 4	» 00 01 10		Internal DCE transmit clock source. External DTE transmit clock source. Remote DCE transmit clock source.
6	0 » 1		CCITT mode. Bell mode.

BIT-MAPPED REGISTER S28
Format		AT [cmds] S28=n [cmds]
Example:		AT S28=0 <CR>
Default:		0
Range:		0 - 155
Unit:		Bit-mapped
Description:		Controls V.23 split speed/direction, pulse dialing and link negotiation speed.
Bit	Value		Function
0	0 1		V.23 split speed operation disabled. V.23 split speed operation enabled.
1	0 1		Select 75bps transmit, 1200bps receive. Select 1200bps transmit, 75bps receive.
2	0		Not used
4, 3	00 01 10 11		39ms make/61ms break at 10pps. 33ms make/67ms break at 10pps. 39ms make/61ms break at 20pps. 33ms make/67ms break at 20pps.
5	0		Not used
7, 6	00 01 10		Link at highest speed possible. Link at 1200bps. Link at 4800bps.

BIT-MAPPED REGISTER S31
Format		AT [cmds] S31=n [cmds]
Example:		ATS31=2<CR>
Default:		2
Range:		0 - 10
Unit:		Bit-mapped
Description:		Controls auto-line speed, and displays error correction progress messages.
Bit	Value		Function
0	0		Not used.
1	0 » 1		Automatic mode detection disabled. Automatic mode detection enabled.
3, 2	» 00 01 10		DTE speed only. Full reporting. DCE speed only.

BIT-MAPPED REGISTER S39
Format		AT [cmds] S39=n [cmds]
Example:		ATS39=3<CR>
Default:		3
Range:		0 - 6
Unit:		Bit-mapped
Description:		Controls flow control and line type.
Bit	Value		Function
2, 1, 0	000 » 011 100 101 110		Flow control disabled. Hardware flow control enabled. Normal software flow control enabled. Transparent software flow control enabled. Both hardware and software flow control enabled.

BIT-MAPPED REGISTER S40
Format		AT [cmds] S40=n [cmds]
Example:		AT S40=107 <CR>
Default:		107
Range:		0 - 253
Unit:		Bit-mapped
Description:		Controls MNP extended services, fallback to V.22/22bis, power level adjustment, break handling, and MNP block size.
Bit	Value		Function
0	0 » 1		MNP10 disabled. MNP10 enabled.
1	0 » 1		MNP10 at 2400 and 1200bps disabled. MNP10 at 2400 and 1200bps enabled.
2	» 0 1		Power level adjustment disabled. Power level adjustment enabled.
5 - 3	000 001 010 011 100 » 101		\K0 \K1 \K2 \K3 \K4 \K5
7, 6	00 » 01 10 11		Maximum MNP block size is 64 characters. Maximum MNP block size is 128 characters. Maximum MNP block size is 192 characters. Maximum MNP block size is 256 characters.

BIT-MAPPED REGISTER S41
Format		AT [cmds] S41=n [cmds]
Example:		ATS41=3<CR>
Default:		3
Range:		0 - 91
Unit:		Bit-mapped
Description:		Selects compression, retrain and fallback/fall-forward, flow control, and MNP mode.
Bit	Value		Function
1 - 0	00 01 10 » 11		Data compression disabled. MNP5 enabled. V.42bis enabled. MNP5 and V.42bis enabled.
6, 2	» 00 01 10		Retrain and fallback disabled. Retrain enabled. Fallback/fall-forward enabled.
3	» 0 1		Flow control disabled. Flow control enabled.
4	» 0 1		Stream mode for MNP. Block mode for MNP.
5	0		Not used.

BREAK SEND
Type:	Configuration
Format:	AT [cmds] \Bn [cmds]
Example:	AT \B3 &W<CR>
Default:	3
Range:	1-9
Unit:	.1 second
Description:	Sends break to modem.

BREAK TYPE
Type:	Configuration
Format:	AT [cmds] \Kn [cmds]
Example:	AT \K5 <CR>
Description:	Configures action of break signal.
Command		Break from DTE	Modem receives \B	Break received from remote modem
\K0		Online command mode enabled, send no break to remote modem.	Break sent to remote modem and buffered cleared.	Buffers cleared, break sent to DTE.
\K1		Break sent to remote modem and buffered cleared.	Break sent to remote modem and buffered cleared.	Buffers cleared, break sent to DTE.
\K2		Online command mode enabled, send no break to remote modem.	Send break to remote modem immediately.	Break sent immediately to DTE.
\K3		Send break to remote modem immediately.	Send break to remote modem immediately.	Break sent immediately to DTE.
\K4		Online command mode enabled, send no break to remote modem.	Send break with transmitted data.	Break sent with received data to the DTE.
» \K5		Send break with transmitted data.	Send break with transmitted data.	Break sent with received data to the DTE.

CELLULAR MODE
Format		AT [cmds] S201=n [cmds]
Example:		ATS201=32<CR>
Default:		32
Range:		0 - 63
Unit:		Bit-mapped
Description:		Controls cellular power level and compromise equalizer.
Bit	Value		Function
4 - 0	» 00000 00001 00010 00011 ... 01010 01011 ... 11111		Sets initial cellular power level to -26dBm. Sets initial cellular power level to -30dBm. Sets initial cellular power level to -10dBm. Sets initial cellular power level to -10dBm. ... Sets initial cellular power level to -10dBm. Sets initial cellular power level to -11dBm. ... Sets initial cellular power level to -31dBm.
5	0 » 1		Compromise equalizer disabled. Compromise equalizer enabled.

COMPRESSION
Type:	Configuration
Format:	AT %Cn
Example:	AT Q1 %C0 &P1<CR>
Description:	Selects data compression.
Command	Function
%C0	Data compression disabled.
%C1	Data compression enabled.
%C2	V.42bis compression enabled.
» %C3	V.42 and MNP5 compression enabled.

CONNECT MODE
Type:	Configuration
Format:	AT [cmds] \Nn [cmds]
Example:	AT \N0 DT555-1212<CR>
Description:	Sets connect mode.
Command	Function
\N0	Normal mode enabled.
\N1	Direct mode enabled.
\N2	Reliable mode enabled.
\N3	Auto-reliable mode enabled.
\N4	LAPM mode enabled.
\N5	MNP mode enabled.

DISPLAY LINE SIGNAL LEVEL
Type:	Immediate
Format:	AT [cmds] %L [cmds]
Example:	AT %L &W<CR>
Description:	Displays a value of the received line signal level.

DISPLAY LINE SIGNAL QUALITY
Type:	Immediate
Format:	AT [cmds] %Q [cmds]
Example:	AT %Q &W<CR>
Description:	Displays line signal quality.

ERROR CORRECTION REJECTION
Format		AT [cmds] S36=n [cmds]
Example:		ATS36=7<CR>
Default:		7
Range:		0 - 7
Unit:		Bit-mapped
Description:		Configures the modem’s behavior if an error-correcting connection cannot be made.
Bit	Value		Function
0 - 2	000 001 011 100 101 » 111		Modem disconnects. Modem attempts direct connection. Modem attempts normal connection. Modem attempts MNP connection. Modem attempts MNP connection. If it fails, modem attempts direct connection. Modem attempts MNP connection. If it fails, modem attempts normal connection.

FLOW CONTROL
Type:	Configuration
Format:	AT [cmds] \Gn [cmds]
Example:	AT \G1 &K3<CR>
Description:	Selects modem port flow control.
Command	Function
» \G0	Flow control disabled.
\G1	Flow control enabled.

LOCK SERIAL PORT
Type:	Configuration
Format:	AT [cmds] \Jn [cmds]
Example:	AT %L3 %B14 \J0<CR>
Description:	Sets operation of serial port speed.
Command	Function
\J0	Serial speed locked.
\J1	Serial speed follows connect speed.

MAXIMUM BLOCK SIZE FOR TRANSMISSION
Type:	Configuration
Format:	AT [cmds] \An [cmds]
Example:	AT \A3 %C1<CR>
Description:	Sets the maximum transmittable block size.
Command	Function
\A0	Maximum MNP block size is 64 characters.
» \A1	Maximum MNP block size is 128 characters.
\A2	Maximum MNP block size is 192 characters.
\A3	Maximum MNP block size is 256 characters.

MNP10 FALLBACK
Type:	Configuration
Format:	AT [cmds] -Qn [cmds]
Example:	AT *H0 -Q1 <CR>
Description:	Allows MNP10 to fall back to speeds slower than 4800bps.
Command	Function
-Q0	MNP10 at 2400 and 1200bps disabled.
» -Q1	MNP10 at 2400 and 1200bps enabled.

MNP STREAM/BLOCK MODE
Type:	Configuration
Format:	AT [cmds] \Ln [cmds]
Example:	AT \L1 DT555-1212<CR>
Description:	Selects the transfer mode for MNP.
Command	Function
» \L0	Stream mode for MNP enabled.
\L1	Block mode for MNP enabled.

MNP10 COMPRESSION
Type:	Configuration
Format:	AT [cmds] -Kn [cmds]
Example:	AT %C1 -K0 <CR>
Description:	Selects MNP10 data compression.
Command	Function
-K0	MNP10 disabled.
» -K1	MNP10 enabled.

MNP10 LINK NEGOTIATION
Type:	Configuration
Format:	AT [cmds] *Hn [cmds]
Example:	AT *H0 -Q1 <CR>
Description:	Sets the speed at which MNP10 link negotiation will occur.
Command	Function
» *H0	Link will be negotiated at highest possible speed.
*H1	Link will be negotiated at 1200bps.
*H2	Link will be negotiated at 4800bps.

MNP10 POWER LEVEL ADJUST
Type:	Configuration
Format:	AT [cmds] )Mn [cmds]
Example:	AT )M1 %C1<CR>
Description:	Controls automatic transmit power level adjustment during MNP 10 link negotiation.
Command	Function
» )M0	Power level adjustment disabled.
)M1	Power level adjustment enabled.

TEST MODES
Format		AT [cmds] S16=n [cmds]
Example:		ATS16=0<CR>
Default:		0
Range:		0-125
Unit:		Bit-mapped
Description:		Controls loopback tests, analog, digital, remote digital, and self tests.
Bit	Value		Function
0	0 1		Local analog loopback not in progress. Local analog loopback in progress.
1	0		Not used.
2	0 1		Local digital loopback not in progress. Local digital loopback in progress.
3	0 1		Modem not in remote digital loopback. Remote digital loopback in progress.
4	0 1		Remote digital loopback not requested. Remote digital loopback requested.
5	0 1		Remote digital loopback w/ self-test not in progress. Remote digital loopback w/ self-test in progress.
6	0 1		Local analog loopback w/ self-test not in progress. Local analog loopback w/ self-test in progress.

TEST MODE - PTT
Type:	Configuration
Format:	AT [cmds] %TTnx [cmds]
Example:	AT %TT0A &W<CR>
Description:	Send PTT test signals for European line test.
Command	Function
%TT0 - %TT09	DTMF dial tone digits 0 to 9.
%TT0A	DTMF dial tone digit *
%TT0B	DTMF dial tone digit A
%TT0C	DTMF dial tone digit B
%TT0D	DTMF dial tone digit C
%TT0E	DTMF dial tone digit #
%TT0F	DTMF dial tone digit D
%TT10	V.21CH1 mark tone.
%TT11	V.21CH2 mark tone.
%TT12	V.23 back channel mark tone.
%TT13	V.23 main channel mark tone.
%TT14	V.22 mark tone at 600bps.
%TT15	V.22 mark tone at 1200bps.
%TT16	V.22bis mark tone at 2400bps.
%TT17	V.22 answer tone, guard tone if PTT enabled.
%TT18	V.22bis answer tone, guard tone if enabled.
%TT19	V.21CH1 space tone.
%TT20	V.32 tone at 9600bps.
%TT21	V.32bis tone at 14.4Kbps
%TT22	V.17 tone at 14.4Kbps
%TT1A	V.21CH2 space tone.
%TT1B	V.23 back channel space tone.
%TT1C	V.23 main channel space tone.
%TT1D	V.27ter carrier tone.
%TT1E	V.29 carrier tone.
%TT30	On-line Silence; initiate hang up.
%TT31	V.25 answer tone.
%TT32	1800 Hz guard tone.
%TT33	V.25 calling tone at 1300 Hz.
%TT34	1100 Hz Fax calling tone.
%TT40	V.21CH2 tone.
%TT50	V.34 tone at 14.4Kbps.
%TT51	V.34 tone at 16.8Kbps.
%TT52	V.34 tone at 19.2Kbps.
%TT53	V.34 tone at 21.6Kbps.
%TT54	V.34 tone at 24Kbps.
%TT55	V.34 tone at 26.4Kbps.
%TT56	V.34 tone at 28.8Kbps.

CALL REQUESTED NUMBER
Type:	Immediate
Format:	CRI<#>;xxxx
Example:	CRI1-303 555-1212;fubar<CR>
Description:	Same as CRN. Dials the number given. It will ignore spaces and hyphens in the string. If the string is more than fifty characters long, a result of INV will be returned and the identification string xxxx will be ignored.

REQUEST LISTED NUMBERS
Type:	Immediate
Format:	RLN
Example:	RLN<CR>
Description:	Requests the modem to return the list of stored numbers. If no numbers are stored, the modem will return LSN.

LOCAL CONFIGURATION
Type:	Immediate
Format:	CNLx [cmds]
Example:	CNL &V0<CR>
Description:	Executes AT command x.