C-2 APPENDIX C: SPECIFICATIONS

RS-232 COM Port Pin Specifications

The asynchronous RS-232-D COM port on the 3C882 ISDN modem, labeled RS-232, is a standard DB-25 female connector. The 3C882 ISDN modem asynchronous port pin assignments, shown in Table C-1,conform to standard definitions for data communications equipment (DCE).

Table C-1 Pin Descriptions

Pin #

Pin Name

Signal Direction

 

 

 

1

Shield Ground (GND)

—

2

Send Data (SD)

To ISDN modem

3

Receive Data (RD)

From ISDN modem

4

Request to Send (RTS)

To ISDN modem

5

Clear to Send (CTS)

From ISDN modem

6

Data Set Ready (DSR)

From ISDN modem

7

Signal Ground (GND)

—

8

Carrier Detect (DCD)

From ISDN modem

18

Local Loopback

From ISDN modem

20

Data Terminal Ready

To ISDN modem

 

(DTR)

 

21

Remote Loopback

To ISDN modem

22

Ring Indicator (RI)

From ISDN modem