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To avoid damage when drilling, ensure that both sides of the mounting surface are clear of
3. The line balance assembly is supplied without conduit or cable entry holes. Drill
or punch the necessary conduit or cable openings in the enclosure before mount-
ing it to the surface. Remove all the metal shavings and debris from the enclosure.
4. Drill four holes at the scribed mounting hole locations. Remove all burs and sharp
edges. Secure the housing to the surface with the user-supplied hardware.
5. Attach the conduit to the enclosure. Feed the wiring through the conduit, and bring
it into the enclosure.
6. Connect an 18AWG twisted pair wire between SelectFone station L1 PAGE L2
and Line Balance L1 PAGE-L2 terminals. Similarly connect the 18 AWG twisted
pair wire for each channel line between terminals of LINE-BALANCE assembly
and corresponding SelectFone station terminals as shown in Figures 1, 4, 5, and
6.
IV. ADJUSTMENTS AND OPERATION.
After all of the stations, the line balance assembly, and paging speakers have been installed and the
wiring is complete, the system should be evaluated and adjustments made to ensure proper operation.
Before beginning, verify that all station handsets are on hook.
Turn on AC power to the system and begin the evaluation at the SelectFone station closest to the line
balance assembly. Lift the handset off hook; the off-hook indicator should turn on. Press the push-to-
page switch on the handset and speak firmly and directly into the handset microphone, verifying that
the message is audible over all speakers except those associated with that station. When paging, if the
line balance assembly is connected properly and the page line is loaded properly, very little or no
message should be heard on the handset receiver. If necessary, open the cover of the line balance
assembly and adjust the page line loading by turning the control to the point where little or no page is
audible in the handset receiver. In the future, if 10 or more units are added to the system, this adjust-
ment may again be necessary.
After line balance adjustments are completed for the page line, the paging speaker volume level can be
adjusted on the associated speaker/amplifier module. To access the speaker/amplifier volume level
control, remove the station cover. The station is pre-set at the factory to produce 1/2 the maximum
output level with moderate page line input.
Check the operation of all channels by holding a conversation between two or more SelectFone sta-
tions on each channel. If the line balance assembly is properly connected, the speaker should hear little
or none of his own voice in the handset receiver. No channel line load adjustment is provided.
The handset transmitter signal is amplified by the handset/amplifier. The handset amplifier has a trans-
mitter volume control and receiver level control. To access these controls remove the front cover of the
station. These controls are located on the printed circuit board mounted to the back of the front cover
and can be adjusted with a small screwdriver. These controls are pre-set at the factory to produce
optimum results in the industrial environment. Before attempting to adjust these controls, check for a
missing or improperly connected line balance assembly, crossed wires, or grounded wires. Stations
located far (3000 feet or more) from the line balance assembly may require that the receiver level
control be adjusted to compensate for cable resistance.
V. TROUBLESHOOTING
In an SelectFone system, AC power circuit conductors are in the same cable with communication
conductors. Even if the system is properly installed, there is an AC voltage between page line or chan-
nel line conductors and ground. This is a result of the induced voltage that is due to the capacitance of
any parts or wires. Drill the holes only through the desired surface.
CAUTION
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