AT&T Merlin 820 Service And Maintenance Manual page 21

Go to the control unit and locate the Voice Terminals jack numbers that
Step 4.
are the same as the intercom numbers of the two voice terminals you have
been using. Switch the cords that are connected to these two Voice Ter-
minals jacks (see Figure 5).
VOICE TERMINAL
(WITH TROUBLE)
VOICE TERMINAL
(WITHOUT TROUBLE)
Figure 5—Switching Cords at the Control Unit
103A MODULAR
JACKS
Basic Trouble Tests
SWITCH
CORDS HERE
CONTROL UNIT
JACK FIELD
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