PCIe-COM-8SM / -4SM User Manual
16
Chapter 6: Connector Pin Assignments
Input/Output Connections
The serial communications ports are interfaced at the card mounting bracket via a female 68-
pin VHDCI D-connector. There are two different breakout cables available terminating in eight
(or four) individual D-sub 9-pin connectors. These cables are permanently labeled near each
DB9 connector with the port letter. The cable that ships as standard is black PVC and the
DB9 pin-out is listed in Table 6-1. Four port cards ordered with a breakout cable will have four
D-sub 9-pin connectors, labeled as COM A, COM B, COM C and COM H.
PIN
RS-232
RS-422 and 4-Wire RS-485
2-Wire RS-485
1
DCD
TX-
-
2
RX
TX+
-
3
TX
RX+
TX+/RX+
4
DTR
RX-
TX-/RX-
5
GND
GND
GND
6
DSR
-
-
7
RTS
-
-
8
CTS
-
-
9
RI
-
-
Table 6-1: DB9 Male Connector Pin Assignments on Standard Cable
Figure 6-1: Male DB9 Connector Pin Locations
For applications that require a 2-wire RS-485 pin-out that is compatible with our PCI-COM485-
8 card and br
eakout cable, specify the card model ending in “NC” (no cable) and the legacy
cable (see ordering guide). This legacy compatibility cable is easily identified as it is light
beige in color, while the standard cable is black molding with a black cable jacket. The RS-485
pin-out for the DB9 connectors on that cable follows:
PIN
2-Wire RS-485
1
TX/RX-
2
TX/RX+
3
TX/RX-
4
-
5
GND
6
-
7
-
8
-
9
TX/RX+
Table 6-2: DB9 Male Connector Pin Assignments on Legacy CAB-PCIe-485-8
