User`s manual

Universal PCI Board User’s Manual Hardware Installation
2-6
CP-118U
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, S2, and S3, are used to select RS-232, RS-422, or RS-485 mode for
each serial port. There are 8 switches on each bank corresponding to the 8 serial ports. S3 selects
between RS-232 and RS-422/485, S2 selects between RS-422 and RS-485, and S1 selects between
2-wire and 4-wire RS-485, as follows:
Mode S1 S2 S3
RS-232 --- --- ON
RS-422 --- ON OFF
4-wire RS-485 ON OFF OFF
2-wire RS-485 OFF OFF OFF