Sigtronics US-12D - Manual (Page 3)

applications* these screws can be installed with no pre-
drilling. Just power in the screws with a standard electric
driver with a 5/16” hex bit. * No pre drilling required for alu-
minum and steel. 1/8” inch pilot hole will still be required
with some stainless steels.
3. Place the intercom back into the bracket and replace
the four washers and two knobs. Set the Intercom to the
desired angle before tightening down the knobs.
II. HEADSET JACK AND PTT SWITCH INSTALLATION
Headset Jack Placement:
It is assumed that it has already been determined which
positions on the vehicle will have headsets. At this stage, it is
helpful to have a headset handy to physically gauge the best
place for a particular jack. There are several things to consider
when selecting a place to mount the headset jacks:
1. In general, for headset positions inside the vehicle, the
jacks should be placed towards the middle between the
user’s positions. They should also be placed up above and
towards the back of the user’s head. This will assure that
the headset cord will not hang between the user and the
vehicle door.
2. The headset jack should be out of the way so that the
headset plug can’t be hit during use or when entering or
exiting the vehicle.
3. The jack position should also take into account how the
headset cord will hang when the headset is in use. The cord
should hang out of the way and should not interfere with
vehicle controls.
4. Verify that the jack placement and headset cable do not
interfere with the normal operation of vehicle doors or
compartments.
5. In vehicles with intercom headset positions installed in
open jump seat locations, the combination of wind, road,
and engine noise, picked up by these jump seat headsets,
can in some cases produce excessive background noise
in the intercom system. Additionally, wide variations in
engine noise (from idle to high RPM) can falsely trigger
the intercom VOX (voice activated) feature. This is espe-
cially true for older vehicles with open jump seats located
next to the vehicle engine. There are two solutions for this
situation. The first one is the recommended one:
a) Order an additional Push-To-Talk (PTT) switch (and
mounting box if needed) for each open jump seat
position. These switches can be conveniently mounted
at each jump seat location and wired so that the jump
seat headset microphone is disabled until the switch is
pressed. See Figure 2 below. The user then presses his
PTT button to talk on the intercom. PTT buttons wired
in this way only activate the intercom. They do not let
the jump seat locations talk on the vehicle radio(s).
b) Order Sigtronics headsets (Models SE-8P, SE-48P, or SE-
18P) with the intercom PTT switch already mounted on
the ear cup for the open jump seat positions. The user
then presses the PTT button on his headset ear cup to
talk on the intercom. The advantage of this method is
that it eliminates having to mount and wire in addi-
tional PTT buttons for the jump seats. Note, however,
most departments prefer to have all the headsets on the
vehicle(s) the same so that any headset can be used in
any position. The headsets with intercom PTT switches
on them cannot easily be used in a position that has
radio transmit capability such as the Driver or Officer
position.
Sigtronics provides two ways to mount the headset jacks for
the UltraSound unit:
1. Mount the jacks in the supplied blue jack boxes.
Advantages:
a) Little or no “behind the panel” space required.
b) No vehicle panel thickness limitation.
c) No large holes are required to be drilled - a real advan-
tage on vehicles with thick metal panels.
d) Complete electrical isolation of the jacks from the
vehicles chassis, because the jack box is fabricated out
of non conductive high impact plastic.
2. Mount the jacks directly on the vehicle with a “through the
panel” mounting scheme. Advantages:
a) Smaller space requirement. (Only slightly larger than the
jack itself).
b) Only one hole to drill per jack (1/2 inch).
c) Most of jack is behind panel and out of the way.
Sigtronics recommends that you use the jack box mounting
method, but either approach can be used as well as a com-
bination of both.
3
VOLUME SQUELCH
INTERCOM
SEE TEXT
UltraSound
TAN
TIP RING
BARREL
HEADSET JACK
INTERCOM PTT SWITCH
BLUE
BLACK
OPEN JUMP SEAT WIRING DIAGRAM
FIGURE 1
FIGURE 2