Rs-232c – HP 16500B User Manual

Page 128

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RS-232C

The logic analysis system interfaces with RS-232C communication lines through a
standard 25 pin D connector. The logic analysis system is compatible with RS-232C
protocol. When a hardwire handshake method is used, the Data Terminal Ready
(DTR) line, pin 20 on the connector, is used to signal if space is available for more
data in the logical I/O buffer. Pin outs of the RS-232C connectors are listed in the
following table.

RS-232C Signal Definitions

Pin
Number

Function

RS-232C
Standard

Signal Direction and Level

1

Protective Ground

AA

Not applicable

2

Transmitted Data (TD)

BA

Data from Mainframe
High = Space = "0" = +12 V
Low = Mark = "1" = –12 V

3

Received Data (RD)

BB

Data to Mainframe
High = Space = "0" = +3 V to +25 V
Low = Mark = "1" = –3 V to –25 V

4

Request to Send (RTS)

CA

Signal from Mainframe
High = ON = +12 V
Low = OFF = –12 V

5

Clear to Send (CTS)

CB

Signal to Mainframe
High = ON = +3 V to +12 V
Low = OFF = –3 V to –25 V

6

Data Set Ready (DSR)

CC

Signal to Mainframe
High = ON = +3 V to +25 V
Low = OFF = –3 V to –25 V

7

Signal Ground

AB

Not applicable

8

Data Carrier Detect (DCD)

CF

Signal to Mainframe
High = ON = +3 V to +25 V
Low = OFF = –3 V to –25 V

20

Data Terminal Ready (DTR)

CD

Signal from Mainframe
High = ON = +12 V
Low = OFF = –12 V

23

Data Signal Rate Selector

CH/CI

Signal from Mainframe
Always High = ON = +12 V

8–19

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