rtd cpuModule CMX47786HX, User Manual

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CMX47786HX RTD Embedded Technologies, Inc.
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Facing the serial port’s connector pins, the pinout is:
RS422 or RS485 Serial Port
You may use BIOS Setup to configure the serial port as RS422 or RS485. In this case, you must
connect the serial port to an RS422 or RS485 compatible device.
When using RS422 or RS485 mode, you can use the port 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 the table below.
When using half-duplex in RS-485 connect the ports as shown in the table below.
9 7 5 3 1
GND DTR TXD RXD DCD
GND RI CTS RTS DSR
10 8 6 4 2
NOTE! A 120 ohm termination resistors is provided on the cpuModule. Termi-
nation is usually necessary on all RS422 receivers and at the ends of the
RS485 bus.
If the termination resistor is required, it can be enabled by closing jump-
er JP1 for Serial Port 1, or JP2 for Serial Port 2.
Table 8: RS-422 Serial Port Connections
Port 1 Port 2
RXD+ TXD+
TXD+ RXD+
RXD- TXD-
TXD- RXD-
Table 9: RS-485 Serial Port Connections
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-