Rs-232c – HP 16500B User Manual
Page 128
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