Westermo ED-20 - Manual (Page 13)

13 6609-2222
Termination and fail safe
(4-wire) Channel 1
Port type
Channel 1
ON
1 2 3 4 5 6 7 8
S1 RS-422
ON
1 2 3 4 5 6 7 8
S1 RS-232
Factory settings
ON
1 2 3 4 5 6 7 8
S2 Not used
ON
1 2 3 4 5 6 7 8
S1 Channel 1
ON
1 2 3 4 5 6 7 8
S1
Termination
and fail safe off
ON
1 2 3 4 5 6 7 8
S1
120
Ω
termination
between R+ and R–
Terminal open interpreted
as Mark (1)
IC2
Not used with RS-232
S2: 1–8
S1: 1–8