CONNECTIONS
Purpose	Location	Purpose	Location
Line out	CN1	RS-232/422	CN4
Line in	CN2	Power switch	SW1
DC power	CN3

DIAGNOSTIC LED(S)
LED	Color	Status	Condition
HS	Red	On	Modem is operating at 2400bps
HS	Red	Off	Modem is operating at less than 2400bps
AA	Red	On	Auto answer enabled
AA	Red	Off	Auto answer disabled
CD	Red	On	Carrier signal detected
CD	Red	Off	Carrier signal not detected
OH	Red	On	Modem is off-hook
OH	Red	Off	Modem is on-hook
RD	Red	On	Modem is receiving data
RD	Red	Off	Modem is not receiving data
SD	Red	On	Modem is transmitting data
SD	Red	Off	Modem is not transmitting data
TR	Red	On	DTR signal is high
TR	Red	Off	DTR signal is low
TM	Red	Blinking	Test mode enabled
TM	Red	Off	Test mode disabled

BIT-MAPPED REGISTER S14
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 S21
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		Restore profile 0 on power-up. Restore profile 1 on power-up.
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 signal forced high. DCD signal normal.
6	» 0 1		DSR signal forced high. DSR signal 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=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 pulse ratio at 10pps (North America) 33/67ms pulse ratio at 10pps (Europe)

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	0 1		Remote digital loopback response disabled. Remote digital loopback response enabled.
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 01 11		Even parity detected. Odd parity detected. No parity detected.
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=77<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	000 001 010 011 100 101 110		Asynchronous mode, serial port speed follows connect speed. Asynchronous command mode and synchronous connect mode. Asynchronous command mode - modem autodials first number in directory on high DTR, then synchronous connect mode. Asynchronous command mode on low DTR, synchronous connect mode on high DTR. Hayes AutoSync™ mode - serial port locked at 9600bps. Error-correcting mode. Asynchronous mode, serial port speed locked.
2	» 0 1		Select dial-up line. Select leased line.
5, 4	00 01 10		Modem generates clock Modem generates clock from the receive carrier signal. DTE generates clock
6	» 0 1		Select CCITT protocols. Select Bell protocols.
7	0		Not used.

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	Data compression enabled.

COMPRESSION MODE
Type:	Configuration
Format:	AT #Ln
Example:	AT #L2 -K1 <CR>
Description:	Selects active compression protocols.
Command	Function
#L0	Compression disabled.
#L1	MNP compression only enabled.
#L2	V.42bis compression only enabled.
» #L3	MNP and V.42bis 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.

INACTIVITY TIMER
Type:	Configuration
Format:	AT [cmds] \Tn [cmds]
Example:	AT\T20<CR>
Default:	0
Range:	0-42
Unit:	1 minute
Description:	Sets the length of time that the modem does not receive information before it disconnects.

LOOPBACK TESTS
Format		AT [cmds] S16=n [cmds]
Example:		ATS16=32<CR>
Default:		0
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.