BIT-MAPPED REGISTER
Format		AT [cmds] S14=n [cmds]
Example:		ATS14=139<CR>
Default:		171
Range:		0 - 255
Unit:		Bit-mapped
Description:		Controls echo, quiet mode, result codes, dial mode, and originate/answer mode.
Bit	Value		Function
0	1		Not used.
1	0 » 1		Command echo function disabled. Command echo function enabled.
2	» 0 1		Result code sending disabled. Result code sending enabled.
3	0 » 1		Numeric format enabled. Verbose format enabled.
4	0		Not used.
5	0 » 1		Tone dialing mode enabled. Pulse dialing mode enabled.
6	» 0 1		Result codes normal. Result codes disabled in answer mode.
7	0 » 1		Answer mode enabled. Originate mode enabled.

BIT-MAPPED REGISTER
Format		AT [cmds] S21=n [cmds]
Example:		ATS21=1<CR>
Default:		0
Range:		0 - 255
Unit:		Bit-mapped
Description:		Controls low DTR action, DCD signal, and the Long Space Disconnect function.
Bit	Value		Function
0	0		Not used.
1	» 0 1		Profile 0 enabled. Profile 1 enabled.
2	0		Not used.
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
Format		AT [cmds] S22=n [cmds]
Example:		ATS22=114<CR>
Default:		118
Range:		0 - 255
Unit:		Bit-mapped
Description:		Controls volume and speaker settings, result codes, and make/break pulse ratio.
Bit	Value		Function
1, 0	00 01 » 10 11		Lowest volume setting. Low volume setting. Medium volume setting Highest volume setting.
3, 2	00 » 01 10 11		Speaker disabled. Speaker enabled until carrier signal detected Speaker enabled. Speaker enabled following dialing, then disabled after carrier signal detected.
6, 5 ,4	000 100 101 110 » 111		Busy and dialtone detection disabled, result codes 0-4 enabled. Busy and dialtone detection disabled, result codes 0-5, 10 enabled. Busy tone detection disabled, dialtone detection enabled, result codes 0-6, 10 enabled. Busy tone detection enabled, dialtone detection disabled, result codes 0-5, 7, 10 enabled. Busy and dialtone detection enabled, result codes 0-7, 10 enabled.
7	0 1		39/61ms at 10pps (North America) 33/67ms at 10pps (Europe)

BIT-MAPPED REGISTER
Format		AT [cmds] S23=n [cmds]
Example:		ATS23=114<CR>
Default:		0, read-only (see note)
Range:		0 - 255
Unit:		Bit-mapped
Description:		Controls guard tones. Also indicates detected serial port speed and parity. Also provides storage for remote digital loopback tests.
Note:		All bits except bits 6 and 7 are read-only.
Bit	Value		Function
0	N/A		Reserved for internal use.
3, 2, 1	000 001 010 011 100 » 101		Local speed detected at 300bps. Local speed detected at 600bps. Local speed detected at 1200bps. Local speed detected at 2400bps. Local speed detected at 4800bps. Local speed detected at 9600bps.
5, 4	» 00 10 11		Even parity. Odd parity. No parity.
7, 6	» 00 01 10		Guard tone disabled. 550Hz guard tone enabled. 1800Hz guard tone enabled.

COMPRESSION
Type:	Configuration
Format:	AT %Cn
Example:	AT %C0 #L0<CR>
Description:	Selects data compression.
Command	Function
%C0	Data compression disabled.
» %C1	Data compression enabled.

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

ID DISPLAY
Type:	Immediate
Format:	AT [cmds] In [cmds]
Example:	AT I1 &W<CR>
Description:	Displays modem properties.
Command	Function
I0	Display product code.
I1	Display checksum.
I2	Display checksum check.
I3	Display version number.

INACTIVITY TIMER
Type:	Register
Format:	AT [cmds] \Tn [cmds]
Example:	AT\T20<CR>
Default:	0
Range:	0-255
Unit:	1 second
Description:	Sets the length of time that the modem does not receive information before it disconnects.

LOOPBACK TEST
Format		AT [cmds] S16=n [cmds]
Example:		ATS16=40<CR>
Range:		0 - 190
Unit:		Bit-mapped
Description:		Configures loopback test options.
Bit	Value		Function
0	0 1		Local analog loopback disabled. Local analog loopback enabled.
1	0		Not used.
2	0 1		Local digital loopback disabled. Local digital loopback enabled.
3	0 1		Remote digital loopback not in progress. Remote digital loopback in progress.
4	0 1		Remote digital loopback disabled. Remote digital loopback enabled.
5	0 1		Remote digital loopback with self test disabled. Remote digital loopback with self test enabled.
6	0 1		Local analog loopback with self test disabled. Local analog loopback with self test enabled.
7	0		Not used.

BIT-MAPPED REGISTER
Format		AT [cmds] S27=n [cmds]
Example:		ATS27=201<CR>
Default:		73
Range:		0 - 255
Unit:		Bit-mapped
Description:		Controls communications mode, line type, and protocol type.
Note:		Be aware that bits 2 and 3 are out of order.
Bit	Value		Function
3, 1, 0	000 001 101 110		Asynchronous mode, serial port speed follows connect speed. Asynchronous off-line command mode and synchronous connect mode. Error-correcting mode. Asynchronous mode, serial port speed locked.
2	0 1		Switched line enabled. Leased line enabled.
4	0		Not used.
5	0		Not used.
6	0 1		Select CCITT protocols. Select Bell protocols.
7	0		Not used.

COMPRESSION
Type:	Register
Format:	AT [cmds] S41=n [cmds]
Example:	ATS41=201<CR>
Description:	Selects data compression.
Command	Function
S41=0	Data compression disabled.
» S41=1	Data compression enabled.