3
OPERATION
Figure 4 shows a V-9924B simplified schematic.
When the V-9924B is idle, 1T IN is shorted to 1T
OUT, 1R IN is shorted to 1R OUT, 2T IN is shorted
to 2T OUT, 2R IN is shorted to 2R OUT, 3T IN is
shorted to 3T OUT, and 3R IN is shorted to 3R OUT.
A signal appearing at the T IN, R IN terminals will
also appear at the T OUT, R OUT terminals for each
zone.
Signaling
When ringing or buzzer voltage appears at the
signaling input leads of the V-9924B, or UNA
closure pins are connected, relays are energized and
the 1T OUT, 1R OUT, 2T OUT, 2R OUT, 3T OUT,
and 3R OUT leads are switched to the outputs of
three 5 Watt amplifiers (One for each zone). At the
same time, the electronic warble tone is connected to
the input of each of the amplifiers and the warble
signal (Will follow the interrupted ringing pattern) is
broadcast to all of the speakers. Each zone has its
own volume control so the volume can be set to a
comfortable level.
Pitch Control
A pitch control has been provided to vary the pitch of
the warble ring tone should a different pitch be
desired. Generally, this control does not require
adjustment (See Figure 2).
TECHNICAL ASSISTANCE
When trouble is reported, verify power is being
supplied to the unit, buzzer, ringing voltage or
contact closure appears at the unit and that there are
no broken connections at the punchdown block. To
effectively test the unit, a VOM and a lineman's test
set will be required. Use the VOM to check for
voltage from the power supply and to verify that
buzzer or ringing is coming from the telephone
system. The lineman's test set can be used to check
for the warble tones on the T OUT and R OUT leads
to the speaker. If a spare unit is available, continue
to troubleshoot by substituting a spare unit for the
suspected unit.
Assistance in troubleshooting is available from the
factory. When calling, you should have a VOM, a
telephone test set available and call from the job site.
Call (540) 563-2000 and Press 1 for
Technical Support, or visit our website at
http://www.valcom.com.
TO REMOVE COVER
LOOSEN SCREW,
THEN ACTIVATE LATCH
PLASTIC
COVER
CIRCUIT BOARD
HOUSING ASSEMBLY
SNAP LATCH
METAL WALL
MOUNTING
PLATE
WIREWAY OPENING
TO WALL PLATE AND
JUNCTION BOX
WIRE TIE LOOP
WIRE TIE USED TO BUNDLE WIRES
ENTERING AND LEAVING TERMINAL AREA
SNAP LATCH
FOR COVER
.155 DIA. HOLES FOR MOUNTING TO
SINGLE OR DOUBLE GANG JUNCTION BOX
HOLE PATTERN MATCHES BOTH EURO
AND US JUNCTION BOXES
1.5 x 2 WIRE ACCESS OPENING
TO JUNCTION BOX
BRACKET
LOCKING
SCREW
FIGURE A
