PCI Quad 422/485 Card
Chapter 2 Hardware Configration
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9
RS485 Multiplex Jumper Settings.
The RS485 Multiplex jumper block, is shown below with default settings of no
jumpers present (both ports full duplex).
Where:
TX/RX1+ and TX/RX1- control port 1 RS485 multiplexing.
TX/RX2+ and TX/RX2- control port 2 RS485 multiplexing.
TX/RX3+ and TX/RX3- control port 3 RS485 multiplexing.
TX/RX4+ and TX/RX4- control port 4 RS485 multiplexing.
Full Duplex Settings(port 1).
Both jumpers left unconnected (not shorted).
Half Duplex Settings(port 1).
Both jumpers shorted, causing the RXD- & TXD- and the RXD+ & TXD+
signals to short together at the 9-pin connector. The multiplex jumpers should
only be set for RS485 Half Duplex operation, when one twisted pair is used to
interconnect both transmit and receive lines.
These settings are the same for each port.
NOTE: Any changes to RS485 Multiplex Operation must be accompanied with
appropriate changes to the driver software
For further details on the RS422 and RS485 standard, pinouts, half duplex and
full duplex RS485 systems, wiring diagrams and optional grounding diagrams
refer to Chapter 10 - "Optional RS422/485 Operation."
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