Moeller DE4-COM-2X Manuel page 84

03/01 AWB823-1279-D/GB/F
h The bus system functions correctly even if one or more
DE4-COM-2X interface modules are no longer connected
to the power supply. However, the respective drive
controllers are then no longer accessible from the control
computer.
Bus termination is normally not necessary. In environments
with heavy electromagnetic interference, connect resistors of
120 O between the two signal cables at each end of the bus.
If a DE4-COM-2X interface module is installed at both ends
of the bus, you can connect the bus terminating resistors
between terminals 71 and 72. The DE4-COM-2X does not
provide for active bus termination.
Wiring with RS 485 Interface
GB-23