Comtech EF Data XPA-200 - Manual (Page 55)

XPA200-7984-I-OPT1, X-Band SSPA Remote Control
XPA200-7984-I-OPT1, Rev.2 5-3
5.3.2.2.1 RS-485 2-wire
The pinout for the 2-wire interface is provided below. Note
that each signal pair (+RX/TX and -RX/TX) is provided on two
pins. This is done to provide customers who are using ‘solder-
cup’ type DB-9 connector the ability to more easily daisy chain
the signals to multiple devices while maintaining one wire per
‘solder-cup’. Customers who use ‘IDC Mass Terminated’ style DB-9
connectors (Ribbon cable types) need only use three (3) signals.
PIN NAME FUNCTION
1 GND Ground
4 +RX/TX Signal Loop In
5 -RX/TX Signal Complement Loop In
8 +RX/TX Signal Loop Out
9 -RX/TX Signal Complement Loop Out
5.3.2.2.2 RS-485 4-wire
The pinout for the 2-wire interface is provided below. Note
that all five (5) signals are required.
PIN NAME FUNCTION
1 GND Ground
4 +TX Transmit Signal
5 -TX Transmit Signal Complement
8 +RX Receive Signal
9 -RX Receive Signal Complement
5.3.3 Cables
5.3.3.1 RS-232
The remote control port is configured with pin 2 as the
transmit data signal (TD) and pin 3 as the receive data signal.
This arrangement allows straight connection (pin 2 to pin 2 and
pin 3 to pin 3) between the SSPA and most standard serial ports
using any standard RS-232C cable (i.e. no need to swap pins 2 and
3).