AT&T Merlin 820 Service And Maintenance Manual page 20

Basic Trouble Tests
VOICE TERMINAL
(WITH TROUBLE)
VOICE TERMINAL
(WITHOUT TROUBLE)
Figure 4—Switching Voice Terminals
Using the voice terminal known to be working, hold the T/P switch in the
Step 3.
T (Test) position.
The same trouble appears,
The trouble does not appear,
Page 16
IF
JACK FIELD
THEN
The trouble is not caused by the
voice terminal. It may be caused
by the control unit, expansion
module, cords, or cables. Return
the voice terminals to their origi-
nal position.
Go on to Step 4.
Trouble found. It is caused by
the first voice terminal.
Read the section on Maintenance
Exchange Procedures at the end of
this manual.
CONTROL UNIT