B-6
the following guidelines to change the termination for your system:
Refer to the circuit board diagram on the previous page for details.
•
If the Base has multiple strings of relays radiating from it, the
Base would
not
be terminated but each Relay would.
•
If the Base is first in a string, (not in the middle or end of a
string), set the 422 jumpers to
Base w/RS-422 termination
.
•
The last Relay in each string should have its jumpers set as a
Relay w/RS-422 termination.
Any Relay that is
not
the last
relay in the string would
not
be terminated.
Relay Station failures are often cable-related. If a Terminal puts
out a “Who Can Hear Me?” message and a Relay that is for some
reason not connected to the Base Station (bad cable, cut cable,
broken connectors) hears it, it answers with the message:
Relay n Cannot Be
Heard by the Base
Notify Supervisor
Press Any Key
At this point, it is up to the operator to notify someone that the Relay is
not communicating with the Base and to check the cabling
first
. There
is no message sent to the host, so it is very important that the operator
that receives this message notify someone immediately.