Black Box 945 User Manual

WATLOW Series 945

How to Use Data Communications

The RS-423A communications uses a three wire (full duplex) system.  There is a
separate line for transmitting, a line for receiving data, and a line for signal common
between the computer and the Series 945.  With RS-423A you can have only one
Series 945 control connected to a single computer or printer.

This diagram is a typical wiring example.  The connections on the host computer
may vary depending on models.  Refer to your computer user's manual for more
information.

945      #1

Signal Common

R

T

Com

Host Computer

(rear view)

T

Jumper to Signal Common

1

2

3

4
5

9

8

7

6

10

11

12

13

14

15

16

17

18

19

2  0

21

22

23

24

25

R

RLSD (Received  Line Signal Detector)

DSR (Data Set Ready)

RTS (Request To Send)

CTS (Clear To Send)

DB-25 female 

connector

(viewed from wire side)

R, and RLSD together.  

S and CTS together.  

mputer's user manual.

DTR (Data Terminal Ready)

3

4

RS-423A