Westermo TD-23 - Manual (Page 18)

18 6600-2204
S2 DIP-switch
Selection of 2/4 wire RS-422/485 side
ON
1 2 3 4 5 6 7 8
4-wire
ON
1 2 3 4 5 6 7 8
Deactivate
RS-422/485
ON
1 2 3 4 5 6 7 8
2-wire
S2 DIP-switch
RTS-CTS delay, 23 or 60 ms
ON
1 2 3 4 5 6 7 8
23 ms
ON
1 2 3 4 5 6 7 8
60 ms
S2 DIP-switch
Termination of the line
ON
1 2 3 4 5 6 7 8
Termination
ON
1 2 3 4 5 6 7 8
No
termination
S2 DIP-switch
Activity timer
ON
1 2 3 4 5 6 7 8
On 1 min
ON
1 2 3 4 5 6 7 8
Off
S2 DIP-switch
Filtering of DCD and RXD
ON
1 2 3 4 5 6 7 8
On
ON
1 2 3 4 5 6 7 8
Off
If this is enabled, RxD is delayed (buffered) 6 ms in order to avoid garbage characters when carrier is deactivated.
The turn around time for the modem from sending to receiving on the line is 10 ms if this filter is enabled.
All RS-422/485 lines should be terminated at the end-points. The RS-422/485 interface also has a fail-sate circuit
which forces a non-active line into idle state.
When a 23 ms delay is chosen, the modem can handle the normal RTS-CTS behavoiur as well as handle that TxD
data is received before the 23 ms delay has elapsed. If TxD data is received before the modem has activated the
CTS signal, the data is buffered. The time the data is delayed depends on how long after the activation of the RTS
the first data bit is received. If a delay of 60 ms is chosen , all data received from the DTE interface (TxD) before
the modem has activated the CTS signal is ignored.
The line should be terminated at the end-points.
S2:6 Not used.
The use of the timer is a fail safe to ensure that a faulty unit connected to the modem will not block the line.
S2:6 Not used.