User`s manual

Universal PCI Board User’s Manual Hardware Installation
2-13
CP-138U-I
Onboard termination resistors can be activated individually for each serial port using jumpers JP1
through JP8. JP1 corresponds to serial port 1. Short the jumper pins to activate the termination
resistor; leave the jumper pins open to bypass the termination resistor.
The onboard DIP switches, S1 and S2, are used to select RS-422 or RS-485 mode for each serial port.
There are 8 switches on each bank corresponding to the 8 serial ports. S2 selects between RS-422
and RS-485; S1 selects between 2-wire and 4-wire RS-485, as follows:
Mode S1 S2
RS-422 --- ON
4-wire RS-485 ON OFF
2-wire RS-485 OFF OFF