Manual 104i-COM-8SM
10
Chapter 3: OPTION SELECTION
To help you locate the jumpers described in this section, refer to the OPTION SELECTION
MAP in
Figure 3-2
, as well as running the SETUP.EXE utility program installed from the
Software Master CD with the software package for this board.
Figure 3-1:
Simplified Dynamic Termination Schematic
Line Terminations
A transmission line should be terminated at the receiving end in its characteristic impedance.
Installing a jumper at the location labeled TX TERM or RX TERM
applies a 120Ω load in
series with a small capacitor across the transmit/receive input/output for RS-485 operation or
input for RS-422 operation respectively.
In RS-485 operations where there are multiple terminals, only the RS-485 ports at each end
of the network should have terminating resistors as described above. Also, for RS-485
operation, there must be a bias on the TX+/RX+ and TX-/RX- lines. If the board is not to
provide that bias, contact the factory technical support.
