Aztech 56K PCI Modem Instrukcja Użytkownika Pobierz pdf (Strona 30)

TECHNICAL REFERENCE

The Serial Interface

The serial interface is a standard developed by the Electronic Industries Association (EIA). It defines

the signals and voltages used when data is exchanged between a computer and a modem or serial

printer.

The entire standard covers many more functions than are used in most data communications

applications. Data is transmitted between the devices over a shielded serial cable with a 25-pin male

(DB-25P) connector to the modem and a 25-pin, 9-pin, 8-pin, or custom-built connector to the

computer.

Pin assignments are factory-set in the 56K Message Modem to match the standard DB-25 assignments

in the following table. DB-9 connectors for IBM/AT-compatible computers should be wired at the

computer end of the cable as shown in the DB-9 column.

Serial Interface Pin Definitions

Signal Source

DB-25DB-9 Circuit Function Computer/Modem

1 — AA Chassis Ground Both

2 3 BA Transmitted Data Computer

3 2 BB Received Data Modem

4 7 CA Request to Send Computer

5 8 CB Clear to Send Modem

6 6 CC Data Set Ready Modem

7 5 AB Signal Ground Both

1 2 ... 25 26 27 28 29 30 31 32

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Aztech 56K PCI Modem Instrukcja Użytkownika Strona 30