Manual

Installation and Hookup 4-9
Publication 999-122 - January 1997
To configure either serial port for RS-422 communications, carefully
move the first (port A) or second (port B) pair of switches to their up
positions using a pen, small screwdriver, etc. For example, the figure
below shows serial port A configured for RS-232 and serial port B
configured for RS-422.
In Multidrop applications, only the first and last IMC-S/23x on the
RS-422 line should be terminated. All intermediate IMC-S/23x
controllers should not have their multidrop serial port terminated. For
example, the figure below shows serial port A configured for RS-232
and serial port B configured for RS-422 without termination.
Port A
Port B
RS-422
220
Ω
RS-422 Term
RS-422 220
Ω
RS-422 Term
DH-485
220
Ω
DH-485 Term
RS-232
No RS-422 Term
RS-232
No RS-422 Term
RS-232/422
No DH-485 Term
Port A
Port B
RS-422
220
Ω
RS-422 Term
RS-422
220
Ω
RS-422 Term
DH-485
220
Ω
DH-485 Term
RS-232
No RS-422 Term
RS-232
No RS-422 Term
RS-232/422
No DH-485 Term