AT&T Merlin 820 Service And Maintenance Manual page 37

Trouble on One Voice Terminal
VOICE TERMINAL
(WITH TROUBLE)
VOICE TERMINAL
(WITHOUT TROUBLE)
On both voice terminals, perform the action that revealed the trouble.
Step 4.
IF
The trouble appears on the voice
terminal on which it first
appeared,
The trouble appears on the voice
terminal that at first did not have
the trouble,
Page 34
Figure 10—Voice Terminal Switch
The trouble is caused by some part
of the voice terminal.
Replace the voice terminals as they
were before. Go on to Step 5.
Replace the voice terminals as they
were before. The voice terminal is
OK.
Go to "Test B: Control Unit Test."
CONTROL UNIT
JACK FIELD
THEN