GE Calibur CBR-PB3-WD - Manual (Page 12)

Kalatel CBR-PB3-WD 12 0150-0261A
Termination Switch
Termination is set on SW4 for PORT 0 (Dipswitch #3)
Termination is important whenever multiple PB3
units are interconnected via the unit’s built-in RS-
485 network. The default termination setting on the
ProBridge 3 unit is with termination set to ON.
Whenever there are more than two PB3’s,
termination on some of the PB3 units will change. The first PB3 and the last
PB3 on the RS-485 network will have termination set to ON (Down), all
others between these two units will have their termination set to OFF (Up).
Sample Systems Termination: