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Chapter 6: Connector Pin Assignments
Input/Output Connections
The serial communications ports are available to the user via a female 68-pin VHDCI D-
connector. There is an available breakout cable terminating in eight (or four) individual D-sub
9-pin connectors.
The cable is permanently labeled near each DB9 connector with the port letter. 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.
The RS-232 specification allows for a maximum recommended length of 50' due to the single-
ended signaling line drivers.
To ensure that there is minimum susceptibility to EMI and minimum radiation, it is important
that the card mounting bracket be properly screwed into place and that there be a positive
chassis ground. Also, proper EMI cabling techniques (cable connect to chassis ground at the
aperture, shielded twisted-pair wiring, etc.) should be used for the input/output wiring.
DB-9 Male Pin x=A-H
For best results termination is recommended for any control signals not being used in your
application wherever possible. Typical applications accomplish this by connecting DSR and
DTR to DCD, as well as connecting the RI and CTS pins to the RTS pin.
RS-232 Signal Names
Ch x - 1
Ch x - 2
Ch x - 3
Ch x - 4
Ch x - 5
Ch x - 6
Ch x - 7
Ch x - 8
Ch x - 9
Table 6-1: Connector Pin Assignments
Figure 6-1: Male DB9 Connector Pin Locations
Signal Descriptions
DCD
Data Carrier Detected
RX
Receive Data
TX
Transmit Data
DTR
Data Terminal Ready
GND
Signal Ground
DSR
Data Set Ready
RTS
Request To Send
CTS
Clear to Send
RI
Ring Indicator
PCIe-COM232-8 User Manual
15
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