PPA5xx/15xx communications manual
1-6
1.3 RS232 connections
The RS232 port on the instrument uses the same pinout as
a standard 9 pin serial port on a PC or laptop (9-pin male
‘D’ type).
The instrument will only transmit when CTS (pin 8) is
asserted, and can only receive if DCD (pin 1) is asserted.
The instrument constantly asserts (+12V) DTR (pin 4) so
this pin can be connected to any unwanted modem control
inputs to force operation without handshaking. The
instrument has a weak pull up on pin 1 as many null
modem cables leave it open circuit. In electrically noisy
environments, this pin should be driven or connected to
pin 4.
To connect the instrument to a PC, use a 9 pin female to 9
pin female null modem cable: