BASE I/O ADDRESS SELECTION
Address	SW1/1	SW1/2	SW1/3	SW1/4
COM1: (3F8h)	Off	On	On	Off
COM2: (2F8h)	On	Off	Off	Off
COM3: (3E8h)	Off	On	On	On
COM4: (2E8h)	On	Off	Off	On

INTERRUPT SELECTION
IRQ	SW1/1	SW1/2	J1/A	J1/B	J1/C	J1/D
3	On	Off	Open	Open	Open	Open
4	Off	On	Open	Open	Open	Open
5	Off	Off	Closed	Open	Open	Open
6	Off	Off	Open	Closed	Open	Open
7	Off	Off	Open	Open	Closed	Open

SIGNAL GROUND
Function	JP2
Signal and chassis ground common	Open
Signal and chassis ground separate	Closed
Note: location of JP2 unidentified.

FACTORY CONFIGURED SETTINGS
Jumper	Setting
JP1	Unidentified
Note: location of JP1 unidentified.

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		Profile 0 enabled. Profile 1 enabled.
2
4, 3	» 00 01 10 11		DTR signal normal. Modem goes to command mode on low DTR. Modem sends OK result code when DTR signal normal . Modem resets on DTR signal.
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=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 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:		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 » 101 110		Asynchronous mode, serial port speed follows connect speed. Error-correcting mode. Asynchronous mode, serial port speed locked.
2	» 0 1		Switched line operation enabled. Leased line operation 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=2<CR>
Description:	Selects data compression.
Command	Function
S41=0	Data compression disabled.
S41=1	Data compression enabled.

COMPRESSION
Type:	Configuration
Format:	AT %Cn
Example:	AT %C0 *Y1<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 modem port flow control.
Command	Function
» \G0	Flow control disabled.
\G1	Flow control enabled.

INACTIVITY TIMER
Type:	Register
Format:	AT [cmds] \Tn [cmds]
Example:	AT\T20<CR>
Default:	0
Range:	0-255
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.