34
CMX32M cpuModule
BDM-610000075
Rev B
Facing the serial port’s connector pins, the pinout is:
RS-422 or RS-485 Serial Port
You may use Setup to configure the serial ports as RS-422 or RS-485. In this case, you must connect the serial
port to an RS-422 or RS-485 compatible device.
When using RS-422 or RS-485 mode, you can use the serial ports in either half-duplex (two-wire) or full-duplex
(four-wire) configurations. For half-duplex (2-wire) operation, you must connect RXD+ to TXD+, and connect
RXD– to TXD–.
When using full-duplex (typically in RS-422 mode), connect the ports as shown in Table 17.
When using half-duplex in RS-485 mode, connect the ports as shown in Table 18.
9
7
5
3
1
GND
DTR
TXD
RXD
DCD
GND
RI
CTS
RTS
DSR
10
8
6
4
2
Note
The cpuModule has a 120
Ω
termination resistor. Termination is usually necessary on all RS-422
receivers and at the ends of the RS-485 bus. Termination resistors can be enabled in the BIOS setup utility.
Table 17
Full-Duplex Connections
Port 1
Port 2
RXD+
TXD+
TXD+
RXD+
RXD–
TXD–
TXD–
RXD–
Table 18
Half-Duplex RS-485 Mode
From
To
Port 1 TXD+
Port 1 RXD+
Port 1 TXD–
Port 1 RXD–
Port 1 TXD+
Port 2 RXD+
Port 1 RXD–
Port 2 TXD–
Summary of Contents for BDM-610000075
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