ABORT DIALING
Type:	Register
Format:	AT [cmds] S64=n [cmds]
Example:	AT S64=1<CR>
Description:	Selects whether dialing and handshaking sequences can be interrupted.
Command	Function
» S64=0	Dialing and handshaking are aborted on receipt of a character from the serial port.
S64=1	Characters received from the serial port during dialing and handshaking are ignored.

BIT-MAPPED REGISTER S14
Format		AT [cmds] S14=n [cmds]
Example:		ATS14=139<CR>
Default:		Unidentified
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 enabled. Result code sending disabled.
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 S21
Format		AT [cmds] S21=n [cmds]
Example:		ATS21=1<CR>
Default:		Unidentified
Range:		0 - 255
Unit:		Bit-mapped
Description:		Controls stored profile DTR action, DCD signal, and the Long Space Disconnect function.
Bit	Value		Function
0	0		Not used.
1	0 1		Use stored profile 0. Use stored profile 1.
4, 3, 2	000 001 010 011 100		DTR signal forced high. Modem goes to command mode on low DTR. Modem disconnects on low DTR. Auto-Answer is disabled. Modem is initialized on low DTR. Modem dials default number on low DTR.
6, 5	00 01 10		DCD signal forced high. DCD signal normal. DCD signal forced high except during disconnect.
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=114<CR>
Default:		Unidentified
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		Not used.

BIT-MAPPED REGISTER S23
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	000 001 010 011 100 101 110 111		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. Local speed detected at 19200bps. Local speed detected at 38400bps.
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.

BIT-MAPPED REGISTER S27
Format		AT [cmds] S27=n [cmds]
Example:		ATS27=201<CR>
Default:		Unidentified
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		Not used.
4	0		Not used.
5	0		Not used.
6	0 1		Select CCITT protocols. Select Bell protocols.
7	0 1		DSR forced high. DSR normal.

COMPRESSION
Type:	Register
Format:	AT [cmds] S41=n [cmds]
Example:	AT S41=1<CR>
Description:	Selects data compression.
Command	Function
S41=0	Data compression disabled.
S41=1	MNP data compression enabled.
S41=2	V.42bis data compression enabled.
S41=3	MNP and V.42bis data compression enabled.

COMPRESSION MODE
Type:	Configuration
Format:	AT %Cn
Example:	AT %C1 -K1 -Q0 <CR>
Description:	Selects active compression protocols.
Command	Function
%C0	Compression disabled.
%C1	MNP compression only enabled.
%C2	V.42bis compression only enabled.
» %C3	MNP and V.42bis compression enabled.

DIAL
Type:	Immediate
Format:	AT [cmds] D<#> [; cmds]
Example:	AT D 9W 1-800-555-2345^,,2554#; ATE1<CR>
Description:	Dials telephone number according to any modifiers included in the string..
Command	Function
L	Redial last number dialed.
^	Transmit calling tone.

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.

LOOPBACK TESTS
Format		AT [cmds] S16=n [cmds]
Example:		ATS16=32<CR>
Default:		Unidentified
Range:		0 - 255
Unit:		Bit-mapped
Description:		Enables loopback tests.
Note:		Bit 3 is read-only.
Bit	Value		Function
0	» 0 1		Local analog loopback test disabled. Local analog loopback test enabled.
1	0		Not used.
2	» 0 1		Local digital loopback test disabled. Local digital loopback test enabled.
3	» 0 1		Modem is not performing remote digital loopback test. Modem is performing remote digital loopback test.
4	» 0 1		Remote digital loopback test disabled. Remote digital loopback test enabled.
5	» 0 1		Remote digital loopback with local self-test disabled. Remote digital loopback with local self-test enabled.
6	» 0 1		Local analog loopback with local self-test disabled. Local analog loopback with local self-test enabled.
7	0		Not used.

MNP10 COMPRESSION
Type:	Configuration
Format:	AT [cmds] -Kn [cmds]
Example:	AT %C1 -K1 -Q0 <CR>
Description:	Selects MNP10 data compression.
Command	Function
» -K0	MNP10 disabled.
-K1	MNP10 enabled.
-K2	MNP10 enabled after V.42 answer mode detection.

MNP10 FALL-BACK
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.

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.