Db9 Pin Description; Cable - CommTech Fastcom G422/4-PCIe Hardware Reference Manual

DB9 Pin Description

The FASTCOM: G422/X-PCIe features four (or eight) RS-422/485 channels, which are accessed through the four
(or eight) DB9 connectors on the cable assembly.
The following is a pin description of the DB9 connectors:
PIN NO. SIGNAL NAME
1 SIGNAL GROUND (GND)
2 READY TO SEND (RTS) +
READY TO SEND (RTS) –
3
4 TRANSMIT DATA (TX) +
TRANSMIT DATA (TX) –
5
6 CLEAR TO SEND (CTS) -
7 CLEAR TO SEND (CTS) +
8 RECEIVE DATA (RX) +
RECEIVE DATA (RX) –
9

Cable

We recommend using vinyl-jacketed, shielded, multiple twisted pair cable (30 AWG
wire) for use with the FASTCOM: G422/X-PCIe. The following cable illustration
shows how to connect two RS-422 devices. Note that disabling handshaking can
eliminate CTS/RTS lines.
DIRECTION
GROUND
OUTPUT
OUTPUT
OUTPUT
OUTPUT
INPUT
INPUT
INPUT
INPUT
TX+
TX- TX-
RX+ RX+
RX- RX-
GND GND
RTS+ RTS+
RTS- RTS-
CTS+ CTS+
CTS- CTS-
®
Fastcom : G422/X-PCIe
13
TX+