AT&T Merlin II Installation And Maintenance Manual page 375

Possible Cause
3. Faulty cable connection.
4-44 Procedures for Specific Symptoms
Possible Solution
Step 1. Go to the control
unit and locate the intercom
jacks for the malfunctioning
voice terminal and for a
working voice terminal of
the same type (analog or
digital). Unplug both from
the control unit and replug
the working voice terminal
into the malfunctioning
voice terminal jack. See if
the trouble occurs on the
working voice terminal.
If the trouble no longer
occurs, the trouble is caused
by one of the cables running
to the malfunctioning voice
terminal.
Step 2. Replace each cable
of the wiring run to the
malfunctioning voice
terminal one at a time, and
test the malfunctioninig voice
terminal after each cable is
replaced. If the trouble still
occurs the replaced cable is
not the faulty one. Replace
the next cable.
If the trouble no longer
occurs, you've found the
faulty cable and corrected
the problem.
To Investigate Further
If the trouble still occurs, the
trouble is in the control unit.
Call the equipment supplier
for assistance.
Go to Step 2.