ComSync/PCI-104 Gen 3
Users Guide
www.connecttech.com
Document: CTIM-00122
Revision: 0.01
Page 10 of 11
Connect Tech Inc. 800-426-8979 | 519-836-1291
Date: 2017-01-26
RS485, ½ Duplex Bias/Termination Selection
Each port, has a pair of jumpers which enable bias and termination resistors to be applied to the differential
TX/RX± signal pair. J1/J2 for Port-1 and J3/J4 for Port-2. High resistance biasing is always applied when the
jumpers are not installed. The circuit is implemented as follows. These jumpers should be
removed
for RS422
(full duplex) and RS232 modes of operation. The RX± and CTS± signals have the high resistance (100K) bias
applied permanently.
The jumpers are usually applied in pairs, but they can be used individually for special situations.
Port-1
Port-2
IO Cable
Cable assembly CBG001 (CTIC-00055) can be used with the
ComSync PCI-104 Gen 3
product. It provides a
DB-25 style of connector. The pin assignments for this cable are shown in the table above.
