Card Type	Modem (asynchronous)
Chip Set	Unidentified
Maximum Data Rate	2400bps
Data Bus	8-bit ISA
Data Modulation Protocol	Bell 103/212A ITU-T V.21, V.22, V.22bis

CONNECTIONS
Function	Label		Function		Label
Line in		CN1		Volume		R1
Line out		CN2

SERIAL PORT ADDRESS AND INTERRUPT
Setting	Setting	SW1/1	SW1/2
COM1 (3F8h)	IRQ 4	On	On
COM2 (2F8h)	IRQ 3	Off	On
COM3 (3E8h)	IRQ 4	On	Off
COM4 (2E8h)	IRQ 3	Off	Off

BIT-MAPPED REGISTER S14
Format		AT [cmds] S14=n [cmds]
Default:		170
Range:		0-174
Unit:		Bit-mapped
Description:		Controls echo, result codes and display, dial mode, and answer/originate mode.
Bit	Value	Function
0	0	Not used
1	0 í 1	Command echo disabled Command echo enabled
2	í 0 1	Result codes enabled Result codes disabled
3	0 í 1	Display result codes in numeric format Display result codes in verbose format
4	0	Not used
5	0 í 1	Tone dial enabled Pulse dial enabled
6	0	Not used
7	0 í 1	Answer mode enabled Originate mode enabled

BIT-MAPPED REGISTER S21
Format		AT [cmds] S21=n [cmds]
Default:		48
Range:		0-252
Unit:		Bit-mapped
Description:		Selects CTS/DCD/DSR signals, low DTR action, and the long space disconnect function.
Bit	Value	Function
1, 0	0	Not used
2	í 0 1	CTS follows RTS CTS forced high
4, 3	00 01 í 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 í 1	DCD forced high DCD normal
6	í 0 1	DSR forced high DSR normal
7	í 0 1	Long space disconnect function disabled Long space disconnect function enabled

BIT-MAPPED REGISTER S22
Format		AT [cmds] S22=n [cmds]
Default:		118
Range:		0-255
Unit:		Bit-mapped
Description:		Controls speaker volume and controls, limits results codes, and make/break ratio.
Bit	Value	Function
1, 0	00 01 í 10 11	Off volume Low level volume Medium level volume High level volume
3, 2	00 í 01 10 11	Speaker off Speaker off on carrier Speaker always on Speaker on during handshake
6, 5, 4	000 100 101 110 í 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
7	í 0 1	39/61ms at 10pps (North America) 33/67ms at 10pps (Europe)

BIT-MAPPED REGISTER S23
Format		AT [cmds] S23=n [cmds]
Default:		6
Range:		0-183
Unit:		Bit-mapped
Description:		Grants/denies remote digital loopback, controls DTE rate and parity, and sets guard tone.
Bit	Value	Function
0	í 0 1	Remote digital loopback denied Remote digital loopback allowed
2, 1	00 10 í 11	Sets serial port speed to 0-300bps Sets serial port speed to 1200bps Sets serial port speed to 2400bps
3	0	Not used
5,4	í 00 01 10 11	Parity even Space Parity Parity odd Mark Parity
7, 6	í 00 01 10	Guard tone disabled Guard tone 550Hz enabled Guard tone 1800Hz enabled

BIT-MAPPED REGISTER S27
Format		AT [cmds] S27=n [cmds]
Default:		64
Range:		0-68
Unit:		Bit-mapped
Description:		Selects line type, and ITU-T/Bell modes.
Bit	Value	Function
1, 0	0	Not used
2	í 0 1	Switched line Leased line
5 - 3	0	Not used
6	0 í 1	ITU/T mode Bell mode

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