Sigtronics EAI Operating Instructions - Manual (Page 4)

5. Replace the Adapter circuit back into the chassis. Make sure
that the transmit mic level adjustment(s) lines up with the
hole(s) in the Adapter chassis. Be sure not to pinch any
wires under the panel. Replace the 4 corner panel screws
and tighten.
6. Plug the Intercom unit plug P1 into the mating connector
J1 on the Radio Adapter unit.
If you are installing an EAI-D4 or EAI-D6 continue on with
the following. Otherwise, for a EAI-S4 or EAI-S6 skip down to
“Headset Jack and PTT Switch Installation” below.
Dual Radio Select Switch Cable Installation (EAI-D4 or EAI-
D6):
The dual radio units have an additional switch cable that
allows radio selection. The switches on this cable are designed
to be panel or dash mounted. The other end of this four foot
cable plugs into the Radio Adapter unit.
1. Select a location for the RADIO 1/ RADIO 2 select switches
near the Intercom unit.
2. Use the printed RADIO 1/ RADIO 2 switch panel as a tem-
plate to mark the two switch holes. Drill both holes using
a standard 1/4’ drill.
3. Remove the switch nuts and mount the switches from
the back of the panel or dash with the key slots down. The
smaller of the two switches is the AUTO / BOTH switch and
it mounts on the right.
4. Install the printed switch panel, thread on the switch nuts
and tighten.
5. Plug the switch cable plug P5 into the Radio Adapter J5
connector.
6. Secure the switch cable to the vehicle with suitable ties.
Again, make sure that the cable does not interfere with
anything on the vehicle.
Ill. 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 the 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 especially
true for older vehicles with open jump seats located right
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 firefighter then uses the
PIT button to talk on the intercom instead of the VOX
(voice activated) intercom feature. 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-2P, SE-40P, or SE-
41P) with the intercom PTT switch already mounted on
the ear cup for the open jump seat positions. The fire
fighter then uses the PIT button on his headset ear cup
to talk on the intercom instead of the VOX feature. The
advantage of this method is that it eliminates having to
mount and wire in additional PIT 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 trans-mit capability such as
the driver or officer position.
Sigtronics provides two ways to mount the headset jacks for
the EAI 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) Smaller 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.
4
FIGURE 2
OPEN JUMP SEAT WIRING DIAGRAM
TAN
RING
BLACK
BARREL
HEADSET JACK
BLUE
TIP
INTERCOM PTT SWITCH