(1) At the Remote intercom under test
check that 48V is supplied to terminals 1 and
2 of TBS.
Depress remote intercom intercom
and then MON B button, and
(2) Set VOLUME at halfway position. Set
channels can be monitored. The
LISTEN-TALK switch to LISTEN, press and
will not illuminate but will stay in until re-
release REL button, set power OFF-ON toggle
leased. Press REL button to release any of the
switch to ON and check that the panel fuse does
not indicate as blown.
(3) Depress OPER A pushbutton and RING
(8) If satisfactory TALK or LISTEN op-
eration is not obtained, the gain of the ampli-
pushbutton. Note that OPER A pushbutton il-
fiers must be readjusted or the defective ampli-
luminates and that audible alarm operates.
fier must be replaced.
(43 Depress REL pushbutton and note that
OPER A pushbutton light is estinguished and
(9) `On the central intercom set LISTEN-
the button returns to its normal position.
TALK switch to TALK, depress channels 1
through 20 pushbuttons and request the asso-
(6) Repeat steps 3 and 4
ciated remote unit to speak. Set TALK switch
nel B (OPER B) instead of
A. The OPER B
to LISTEN and check that a reply can be heard.
button should illuminate, and
the alarm should
Adjust VOLUME control for a satisfactory vol-
indicate when the RING button
ume. Repeat this step for the associated station.
(6) Depress LISTEN-TALK switch to
(10) If satisfactory TALK or LISTEN oper-
TALK position and also depress OPER A, or
ation is not obtained the gain of amplifiers 1,
OPER B, button and request central intercom
2, or 3 must be adjusted, or the defective am-
to speak. release LISTEN-TALK switch and
plifier must be replaced.
check that a reply is heard in LISTEN position.