13
Fastcom
®
: G422/X-PCIe
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
DIRECTION
1
SIGNAL GROUND (GND)
GROUND
2
READY TO SEND (RTS) +
OUTPUT
3
READY TO SEND (RTS)
–
OUTPUT
4
TRANSMIT DATA (TX) +
OUTPUT
5
TRANSMIT DATA (TX)
–
OUTPUT
6
CLEAR TO SEND (CTS) -
INPUT
7
CLEAR TO SEND (CTS) +
INPUT
8
RECEIVE DATA (RX) +
INPUT
9
RECEIVE DATA (RX)
–
INPUT
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.
TX+
TX-
RTS+
RTS-
CTS+
CTS-
TX+
TX-
RTS+
RTS-
CTS+
CTS-
RX+
RX-
RX-
RX+
GND
GND
