cmd6686gx manual - RTD Embedded Technologies, Inc.
cmd6686gx manual - RTD Embedded Technologies, Inc.
cmd6686gx manual - RTD Embedded Technologies, Inc.
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Facing the serial port’s connector pins, the pinout is:<br />
9 7 5 3 1<br />
GND DTR TXD RXD DCD<br />
GND RI CTS RTS DSR<br />
10 8 6 4 2<br />
RS422 or RS485 Serial Port<br />
You may use Setup to configure the first serial port as RS422 or RS485. In this case, you must connect<br />
the serial port to an RS422 or RS485 compatible device.<br />
When using RS422 or RS485 mode, you can use the port in either half-duplex (two-wire) or fullduplex<br />
(four-wire) configurations. For half-duplex (2-wire) operation, you must connect RXD+ to<br />
TXD+, and connect RXD- to TXD-.<br />
NOTE!<br />
A 120 ohm termination resistors is provided on the cpuModule. Termination<br />
is usually necessary on all RS422 receivers and at the ends of the<br />
RS485 bus.<br />
If the termination resistor is required, it can be enabled by closing jumper<br />
JP1.<br />
When using full-duplex (typically in 422 mode) connect the ports as shown in the table below.<br />
Full-Duplex Connections<br />
Port 1 Port 2<br />
RXD+ TXD+<br />
TXD+ RXD+<br />
RXD- TXD-<br />
TXD- RXD-<br />
When using half-duplex in 485 connect the ports as shown in the table below.<br />
Half-Duplex 485 Mode<br />
From<br />
Port 1 TXD+<br />
Port 1 TXD-<br />
Port 1 TXD+<br />
Port 1 RXD-<br />
To<br />
Port 1 RXD+<br />
Port 1 RXD-<br />
Port 2 RXD+<br />
Port 2 TXD-<br />
35
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