UNIDENTIFIED

1200/300 BAUD MODEM

Modem Type

Data (synchronous/asynchronous)

Maximum Data Rate

1200bps

Data Bus

8-bit ISA

Data Modulation Protocol

Bell 103 & 212A, ITU-T V.22

Error Correction/Compression

Unidentified

CONNECTIONS

Purpose

Location

Purpose

Location

Line-in

J1

Line-out

J2

INTERRUPT SELECT - JP1

í IRQ

Jumper A

Jumper B

Jumper C

Jumper D

» IRQ4

Open

Open

Closed

Open

í IRQ2

Closed

Open

Open

Open

í IRQ3

Open

Closed

Open

Open

í IRQ5

Open

Open

Open

Closed

ADDRESS SELECT

í COM/Address

SW1/1

SW1/2

» COM1/3F8h

Off

Off

í COM2/2F8h

Off

On

í COM3/3E8h

On

Off

í COM4/2E8h

On

On

RECEIVED LINE SIGNAL DETECT BIT (RLSD)

í Setting

SW1/3

» RLSD bit reset/carrier detect status written to modem status register.

Off

í RLSD bit written to modem status register.

On

DATA TERMINAL READY (DTR)

í Setting

SW1/4

» DTR bit status written to the UART modem control register.

Off

í DTR bit is ignored.

On

PROTOCOL SELECT

Protocol

SW1/5

» Bell 103 & 212A enabled.

Off

í CCITT V.22 enabled.

On

MAKE/BREAK RATIO

í Setting

SW1/6

» 39/61 ratio (Bell standard).

Off

í 33/67 ratio (CCITT standard).

On