Sigtronics Emergency Apparatus Intercom System (EAI)
INSTALLATION AND OPERATING INSTRUCTIONS
Models EAI-S4, EAI-S6, EAI-D4, and EAI-D6
INTRODUCTION
ATTENTION INSTALLER: To assure a trouble free Installation, please read these entire instructions through once
before beginning.
The Sigtronics EAI system, when used with Sigtronics noise
attenuating headsets provides the emergency apparatus
crew with clear, hands free, voice actuated (VOX) intercom.
The system also allows full radio monitoring at all headset
positions as well as radio transmit capability from selected
headsets via Push-To-Talk (PTT) switches.
Applications: The unit is designed for fire apparatus, rescue
and ambulance vehicles, marine emergency equipment, airport ground vehicles, and mobile emergency command
centers.
igtronics
S
Made in the U.S.A.
®
Specialists in “SOUND” Management
178 East Arrow Highway, San Dimas, CA 91773 ( 909 ) 305-9399
Voice Activated Intercom (VOX) feature allows “hands free”
communication between headsets connected to the EAI unit.
Start speaking and the intercom turns on instantly to relay
your message clearly to the other headsets. Stop talking and
it turns off to reduce background noise.
Up to Four Headset Positions can be connected to the
EAI unit. More headset positions can be achieved by wiring
additional jacks in parallel. Only one headset, however, can
be plugged into paralleled jacks at one time. This paralleled
jack scheme is most commonly used on pumper trucks at the
pump panel. In this case, the driver plugs his headset into the
engineer’s jack while driving. He then unplugs and plugs into
the pump panel when he arrives on scene.
Headphone Output: The EAI system is designed to easily
drive six or more 300 to 1000 ohm headsets.
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Noise attenuating, full cushion headsets, such as the
Sigtronics SE-2, or SE-40 are recommended for best results.
The EAI system incorporates an automatic headphone limiting circuit to eliminate the possibility of painful spurious
radio or noise spikes from getting to the headsets and into
your ears.
Universal Radio Interface design to accommodate virtually
any type of communication radio.
Mike Output: Designed to be fully compatible with virtually
all mobile radios used on emergency vehicles. An adjustment
for transmit microphone level is provided to perfectly match
the EAI system to your particular radio. For applications where
a very high transmit microphone level is required (some Midland and Wilson radios), an inexpensive plug in Mic Level
Amplifier module is available.
Automatic Sidetone Generation allows everyone on the
vehicle to hear both sides of the radio conversations.
Excellent RF Immunity guarantees clean, clear, radio communications.
Standardized for use with Sigtronics single plug headsets
(ie. SE-2, SE-40, SE-41).
Model Differences: The EAI-S4 is used in applications requiring up to four persons at one time on intercom and using a
single vehicle radio. The EAI-S6 is identical to the EAI-S4 but
can intercom up to six people at one time. The EAI-D4 is used
in applications requiring four intercom positions and the use
of two separate radios. Similarly, the EAI-D6 is a six place intercom with two radio capability.
CONTROL FUNCTIONS
ON / OFF — Power Switch — In “ON” position; supplies
power to all EAI circuits. In “OFF” position; disables all unit
functions except radio receive.
VOL — Intercom Volume — Adjusts intercom volume level.
Does not affect radio volume.
SQ — Intercom Squelch - Adjusts VOX operation of the intercom for variations in background noise levels.
RADIO 1 / RADIO 2 (TALK) — Transmit Select (EAI-D4 and
D6 units only) — Used to select which radio to talk on -Radio
1 or Radio 2.
AUTO / BOTH (LISTEN) — Receive Select (EAI-D4 and D6
units only) — Used to select which radio is heard. In “BOTH”
position, you hear both Radio 1 and the Radio 2. In “AUTO”
position, only the radio selected by the RADIO 1 / RADIO 2
switch is heard.
RADIO TRANSMIT MIC LEVEL — Sets the transmit mic audio
level for the radio(s).
EAI INSTALLATION
Standard Equipment Included
Besides the Intercom unit and the Radio Adapter unit, each
EAI system comes complete with the following:
EAI-S4/D4 EAI-S6/D6
Intercom Drill Template 1 1
Intercom Panel 1 1
(printed on both sides)
Intercom Control Knobs 2 2
Intercom Switch Nut 1 1
Intercom Panel Screws 2 2
Headset Jack Box 6 6
Headset Jack Box Cover
with Pre-mounted Headset Jack 4 6
with Pre-mounted Headset Jack
& Splash Cover 1 1
with Pre-mounted PTT Switch 1 1
PTT Switch with Hardware
(loose, not in boxes) 2 2
Jack Box Cover Screws 12 16
Jack Box Mounting Screws 12 16
Wire Grommets 6 8
Jack Insulator Washer, Flat 5 7
Jack Insulator Washer, Shoulder 5 7
Radio Adapter Mounting Screws 4 4
Radio Adapter Mounting Nuts 4 4
Male Connector Housing 1 1
Male Crimp Pins 13 15
Female Connector Housing 1 1
Female Crimp Pins 13 15
4 ft. Headset Jack
& PTT Switch Cable 1 1
4 ft. Radio 1/ Power
Interface Cable 1 1
4 conductor hook-up wire 1 Roll 1 Roll
4 ft. Radio 2 Interface Cable 1* 1*
Radio Select Switch Cable 1* 1*
Radio Select Panel 1* 1*
* Supplied with Dual Radio EAI-D4 and EAI-D6 units only.
INSTALLATION OVERVIEW
Sigtronics has simplified the installation process, to assure
perfect operation. Refer to the EAI Wiring Diagram (for EAIS4 or EAI-S6 see Figure 4 on page 6 for EAI-D4 or EAI-D6 see
Figure 5 on page 7). If you have any installation questions or
problems that are not addressed in this manual, feel free to
call our installation hot line number located on the last page
of this manual.
Installation of the Sigtronics EAI System is a five step process:
I. Mount the intercom unit. (Intercom Chassis Installation)
II. Install the Radio Adapter unit. (Radio Adapter Chassis
Installation)
Ill. Install the headset jacks and PTT switches. (Headset Jack
and PTT Switch Installation)
IV. Wire the jacks and PTT switches. (Headset Jack and PTT
Switch Wiring)
V. Wire the radio(s). (Radio Hook Up)
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I. INTERCOM CHASSIS INSTALLATION
Intercom Placement:
There are a few factors to consider when selecting a mounting location for the EAI Intercom chassis unit:
1. The unit should be placed in such a way that its controls
can be easily seen and operated. Most commonly, this will
be near the vehicle’s communication radio controls.
2. The Intercom unit is primarily designed to be panel or dash
mounted. Above and below dash mounting, however, can
be accomplished by fabricating an inexpensive bracket.
3. The intercom unit has been designed to mount either
horizontally or vertically. The printed panel is reversible
for this purpose.
4. The location selected requires a minimum front panel area
of 2 1/2˝ by 1 1/16˝.
5. The intercom unit normally mounts though the panel or
dash. The maximum allowable panel thickness is 5/32 of
an inch. If the panel is thicker than this, the volume and
squelch knobs will not attach on the unit.
6. The depth required behind panel is 4 3/16˝, plus cable
access. Verify that the rear of intercom unit and cable will
not interfere with the normal operation of any vehicle
controls or the operation of vehicle compartment doors.
7. The Radio Adapter part of the EAI system plugs into the
intercom unit. Therefore, they are usually mounted near
each other. If necessary, however, an extension between
the two units can be fabricated. Connectors for this are
included with the system.
8. For dual radio systems (EAI-D4 or EAI-D6), allow for an additional panel space of 1˝ x 1-1/2˝ near the Intercom unit for
the radio selection switches.
Panel Preparation:
1. Once the location is selected, remove the protective paper
from the back of the adhesive drill template. Then stick it
down on the vehicle dash or panel in the selected area.
2. Center punch each hole at the cross lines. (The five holes
are in straight line and equally spaced 0.4˝ apart).
3. Drill 1/8˝ pilot hole at all five places.
4. Enlarge ON / OFF switch hole to 1/4˝ and the volume and
squelch control holes to 3/8˝ per template.
Mounting Intercom Unit: See Figure 1
VEH I CL E
PAN E L
DO N OT RE M OV E
THE S E N UTS
INT E RCOM
INT E RCOM
PAN E L
SWI TCH
NUT
FIGURE 1
KNO B
4– 40 S CR EW S
KNO B
1. Remove the nut from the Intercom unit ON / OFF switch.
2. Remove the two small black Phillips head screws (#4-40)
located on either side of the ON / OFF switch.
3. Remove both knobs from the Volume and Squelch controls
using a standard .050˝ Allen wrench. CAUTION:DO NOT REMOVE the nuts from the Volume and Squelch controls.
4. Insert the Intercom unit from the rear of panel. Arrows on
the top and side of the intercom unit chassis indicate which
way is up. One for horizontal mounting and the other for
vertical.
5. Install the printed Intercom panel and lightly thread on
the ON / OFF switch nut. The nuts on Volume and Squelch
controls should fit inside the drilled 3/8˝ diameter holes.
6. Reinstall and tighten the two small black screws through
the holes in intercom panel. Tighten ON / OFF switch nut.
7. Turn both Volume and Squelch controls fully clockwise.
Reinstall the knobs on Volume and Squelch control shafts.
Without moving the control shafts, align the white line on
the knobs to the five o’clock position. Tighten with the
Allen wrench.
II. RADIO ADAPTER CHASSIS INSTALLATION
Placement:
The Radio Adapter part of the EAI system is designed to
be remote mounted (behind the dash) with four screws
mounted through the grommets on the back of the chassis. Because the Adapter connects to the radio(s), select a
mounting location near the emergency radio controls. Also,
if space allows, mounting this Adapter within a few inches of
the Intercom unit allows connectors P1 and J1 to be mated
directly. An extension can be fabricated if necessary to connect the two together.
Make sure that the transmit mic level adjustment hole(s) on
the side of the Radio Adapter chassis can be easily accessed
for adjustment with the Adapter in place. As usual, with the
Adapter in place, it or its cables should not interfere with the
normal operation of the vehicle.
Mounting Radio Adapter Chassis:
1. Remove the four corner panel screws (the smaller ones)
from the top of the Adapter unit. Remove the unit from
the chassis.
2. Set the Adapter chassis in the intended mounting place.
Using a small point pen or marker, mark the hole pattern
through the four grommets located on the bottom of the
Adapter chassis.
3. Drill four holes using a 5/32 inch drill (clearance for a 6-32
screw).
4. Secure the Adapter chassis to the vehicle using the four
screws and locking nuts supplied. Be sure to install the
screws with the screw heads inside the Adapter chassis.
This should assure that these mounting screws will not
touch the Adapter circuit board when in place. Do not
tighten the nuts and screws so tight as to excessively crush
the grommets.
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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 EAID6):
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 template 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
FIGURE 2
TAN
INTERCOM PTT SWITCH
OPEN JUMP SEAT WIRING DIAGRAM
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.
TIPRING
BARREL
HEADSET JACK
BLUE
BLACK
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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 combination of both.
If required, additional headset jacks, PTT switches, mounting
boxes, and hardware are available through your Sigtronics
dealer.
Splash Cover:
If a jack is to be mounted outside the vehicle (ie. on or near
a fire engines pump panel), a splash cover should be used
to keep excess moisture out of the jack when it is not in use.
Every EAI system comes with one such splash cover already
pre-mounted on a jack in a mounting box. On other positions,
where the headset is always plugged in, a splash cover is not
required.
Jack Box Mounting:
For most installations the wiring for the headset jack will
come out the back of the jack box. Four holes are provided in
the back of the box for mounting and headset jack wiring.
Place the jack box on the mounting surface and mark and
drill the corresponding holes into the vehicle. Use a 1/8 inch
drill for mounting holes, a 1/4 inch drill for the headset jack
wiring. Mount the jack box to the vehicle with the provided
#10 screws. The screws require a 5/16 inch hex driver.
Alternately, the headset jack wire can come out of the side of
the jack box if desired. You will have to drill the hole where
required. Use a 1/4 inch drill. Rubber wire grommets are provided for the wire going through the jack box hole.
SHOULDER
INSULATING
WASHER
TIP
BARREL
RING
HEADSET JACK
FLAT
INSULATING
WASHER
VEHICLE
PANEL
FLAT
METAL
WASHER
NUT – OR – SPLASH COVER AND NUT
FIGURE 3
Through the Panel Mounting:
For direct mounting of headset jacks on the vehicle panel you
will need to remove the jack from the jack box cover with a
1/2 inch wrench. For normal jack mounting (no splash cover),
the maximum panel thickness is 0.10 inches or a little less
than 1/8 of an inch. If you need the splash cover (optional), the
maximum panel thickness is 0.062 inches or 1/16 of an inch.
NOTE: Longer headset jacks that can accommodate thicker
panels are available from your Sigtronics dealer (order part
number 100418 - maximum panel thickness 0.155˝ with
splash cover and 0195˝ without).
Mounting on the panel requires that you insert the jack
from the back of the panel. Test jack(s) for clearance and fit.
Leave room behind - the jack expands when headset plug is
inserted. Make sure the back of the jack does not interfere
with any moving parts of the vehicle.
Drill a 1/2 inch hole in the panel. Install jack with mounting
washers and nut as in Figure 3. Both jack insulating washers
must be used. Jack has to be insulated from mounting spot
to minimize electrical noise getting into intercom system. No
need to tighten the jack now. You may have to remove the
jack to connect the wires.
PTT Switch Installation:
In order for the officers to transmit on their selected radios,
they will each need a Push-To-Talk (PU) switch.
The PTT switches should be placed within easy reach of the
users. It is also helpful if they can be easily seen by the users.
The maximum panel thickness that can accommodate the
switches is 3/16 of an inch. The PTT switches are mounted
through the panel from the front. They can also be mounted
in a jack box.
In the selected spot, drill a 5/8 inch hole. Mount the switch
into the hole but only loosely install the provided lock washer
and nut from the back. The PTT switch will likely have to be
removed to connect the wires later.
IV. HEADSET JACK AND PTT SWITCH WIRING
The wiring of the headset jacks and PTTs is straight forward.
In general, the 4 ft.. Headset Jack and PTT Switch Cable gets
wired to the four conductor Hook-up Wire (gray) and then the
Hook-up wire connects to the jacks and the PTT switches. For
the EAI-S4 and D4 models, this cable has a 12 pin connector
with 8 wires. For the EAI-S6 and D6, there is a 15 pin connector
and 10 wires. Before going on, plug in J2 of the cable into P2
on the Radio Adapter unit.
Flexible four conductor hook-up wire is provided with each
system to connect each headset jack and PTT switch to
the EAI unit’s Headset Jack and PTT Switch Cable. Enough
wire is provided for a typical vehicle installation. If required,
additional hook-up wire can be purchased through your
Sigtronics dealer.
Each headset jack requires three wires. Each PTT switch
requires two. If an officer’s PTT switch and headset jack are
mounted near each other, only four wires are needed. Refer
to the EAI Wiring Diagram (for EAI-S4 or EAI-S6 see Figure 4
on page 6 for EAI-D4 or EAI-D6 see Figure 5 on page 7) for the
exact wiring information.
The connections between the Headset Jack and PTT Switch
Cable and the hook-up wire should be soldered and insulated
for reliability. Do not use crimp type splices. They can become
intermittent over time. Use a good quality electrical tape, or
better yet, use heat shrink tubing to cover the soldered
connections. The connections to the headset jacks and PTT
switches will also have to be soldered. See Figure 3 on page
5 for jack terminal identification.
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SPEAKER HI (2) VIOLET NOTE 1
SPEAKER LO (3) VIOLET NOTE 1
1234
PTT HI (5) WHITE NOTE 2
RADIO
CHASSIS GROUND (8) GREEN
+12 / +24FUSE
VOLTS DC (7) RED
NOTES:
1. CONNEC T EITHER VIOLE T WIRE TO TH E RADIO SPE AKER HI OUTPUT. CONNECT THE
REMAINING VIOLET WIRE TO SPEAKER LO.
2. CONNEC T EITHER WHITE WIRE TO THE RADIO PUSH -TO-TALK ( PTT) KEY LINE INPUT.
CONNEC T THE REMAINING WHITE WIRE TO THE PT T KEY LIN E RETURN (PTT LO ).
3. IF NEEDED, AN EXTENSIO N CABLE MAY BE FABRICATED AND INSERT ED BETWEEN
P1 AND J1. PINS AND CONNEC TORS HAVE BEEN SUPPLI ED.
4. FOR EAI-S6 UNITS CONNECT PIN 13 (TAN ) TO CREW #3 HEADSET JACK RING TERMINAL
AND PIN 14 (TAN) TO CRE W #4 JACK RING TERMINAL . CONNECT BLUE AND BLACK
WIRES TO CREW #3 AND # 4 AS ON OTHER JACKS.
PTT LO (6) WHITE NOTE 2
MIC HI (1) BROWN
MIC LO (4) BLACK
(1 AMP)
SQ
VOL
ON
Intercom
NOTE 3
P1 J1
INTERCOM
UNIT
J3
P3
Radio Transmit
Mic Level
RADIO ADAPTER
UNIT
NOTE 4
J2
P2
EAI-S4 / S6 ( SINGLE RADIO ) WIRING DIAGRAM
(2) WHITE / RED
(1) WHITE / BLACK
(8) TAN
(4) BLACK
(3) BLUE
(9) TAN
(10) WHITE / BLUE
(11) WHITE / ORANGE
(10) WHITE / BLUE
(11) WHITE / ORANGE
PTT SWITCH
TIPRING
BARREL
HEADSET JACK
CAPTAIN
PTT SWITCH
TIPRING
BARREL
HEADSET JACK
DRIVER
FIGURE 4
TIPRING
BARREL
HEADSET JACK
CREW # 1
TIPRING
BARREL
HEADSET JACK
CREW # 2
PTT SWITCH
TIPRING
BARREL
HEADSET JACK
PUMP PANEL
We also do not recommend using screw type terminal strips
for intercom connections. There have been several instances
where terminal strips introduced high levels of electrical
noise like alternator whine into the intercom system. It is
acceptable however to tie the intercom red and green power
wires to existing vehicle terminal strips.
The best place to run the wiring between the unit and the
jack and PTT switches is out of sight. It should be run behind
vehicle panels and/or up in the headliner. This will reduce the
chance of personnel or equipment catching on or damaging the wiring. Wire routing should take into account normal
vehicle operations. Wires should not interfere with any of the
vehicle’s controls, compartments, or doors. If the vehicle’s cab
tilts up for engine servicing, run wiring along the existing
vehicle wiring bundle. Make sure that wiring does not interfere or restrict the tilting operation. Also, make sure that the
tilting operation will not cut or sever the wiring.
Make sure that the wiring does not rest on sharp edges. Over
time the vehicle’s vibration may cause a sharp edge to cut
into the wire. Use the provided wire grommets wherever
the four conductor wire goes through the hole into a jack
box. Use wire ties or tie wraps to secure and strain relieve
the wire.
At this time do not put the covers on the jack boxes or tighten
up the PTT switches. You will need to verify the correct operation of the system before you close everything up.
Power Connections:
The EAI unit will run on 11-34 VDC, so it automatically adjusts
to 12 or 24 volt vehicles. CAUTION: This EAI unit is designed
for negative ground vehicles only. It can be used on positive
ground vehicles only if a Sigtronics Positive Ground Adapter
is used. Contact your Sigtronics dealer on pricing and availability.
Make sure that the vehicle power is turned off before connecting the EAI power wire. The power for the EAI units comes
in on the red and green wires on the Radio 1/ Power Interface
Cable. It is an eight wire cable with a 9 pin connector. Plug
the 9 pin connector J3 into the mating connector P3 on the
Radio Adapter unit.
Connect the red wire to vehicle power. ( Try not to use a power
buss that also runs electrical motors such as fans or light bars
with rotating lights.) Connect the green wire to the vehicle
chassis ground.
INTERCOM WIRING CHECK OUT
System Setup:
Before you connect the vehicle’s radios, check out the system
operation. Do the following without the vehicle’s engine running:
First plug all headsets into the respective headset jacks.
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SPEAKER HI (2) VIOLET NOTE 1
SPEAKER LO (3) VIOLET NOTE 1
1234
PTT HI (5) WHITE NOTE 2
RADIO 2
RADIO 1
CHASSIS GROUND (8) GREEN
+12 / +24FUSE
VOLTS DC (7) RED
PTT LO (6) WHITE NOTE 2
MIC HI (1) BROWN
MIC LO (4) BLACK
SPEAKER HI (2) VIOLET NOTE 1
SPEAKER LO (3) VIOLET NOTE 1
1234
PTT HI (5) WHITE NOTE 2
PTT LO (6) WHITE NOTE 2
MIC HI (1) BROWN
MIC LO (4) BLACK
(1 AMP)
SQ
P1 J1
NOTE 3
VOL
ON
Intercom
INTERCOM UNIT
NOTES:
1. CONNEC T EITHER VIOLE T WIRE TO TH E RADIO SPE AKER HI OUTPUT. CONNECT THE
REMAINING V IOLET WIRE TO SPEAKER LO.
2. CONNEC T EITHER WHITE WIRE TO THE RADI O PUSH-TO-TALK (PTT ) KEY LINE INPUT.
CONNEC T THE REMAINING WHIT E WIRE TO THE PT T KEY LINE RETURN ( PTT LO) .
3. IF NEEDED, AN EXTENSION CABLE MAY BE FABRICATED AND INSERT ED BETWEEN
P1 AND J1. PINS AND CON NECTORS HAVE BEEN SUPPLIED.
4. FOR EAI-D6 UNI TS CONNECT PIN 13 (TAN ) TO CREW # 3 HEADSET JACK RING TERMINAL
AND PIN 14 (TAN) TO CREW #4 JACK RING TERMINAL. CONNECT BLUE AND BLACK
WIRES TO CREW #3 AND #4 AS ON OTHER JACKS.
5. MOUNT SWITCHES W ITH BUSHING KEYSLOT DOWN.
RADIO SELECT SWITCHES
TALK
RADIO 1
RADIO 2
J4
P4
J3
P3
Transmit
Mic Level
Radio 1
Radio 2
RADIO ADAPTER UNIT
P5
J5
LISTEN
AUTO
BOTH
NOTE 5
NOTE 4
J2
P2
EAI-D4 / D6 ( DUAL RADIO ) WIRING DIAGRAM
(2) WHITE / RED
(1) WHITE / BLACK
(8) TAN
(4) BLACK
(3) BLUE
(9) TAN
(10) WHITE / BLUE
(11) WHITE / ORANGE
(10) WHITE / BLUE
(11) WHITE / ORANGE
PTT SWITCH
TIPRING
BARREL
HEADSET JACK
CAPTAIN
PTT SWITCH
TIPRING
BARREL
HEADSET JACK
DRIVER
FIGURE 5
TIPRING
BARREL
HEADSET JACK
CREW # 1
TIPRING
BARREL
HEADSET JACK
CREW # 2
PTT SWITCH
TIPRING
BARREL
HEADSET JACK
PUMP PANEL
Put on one of the headsets and position the boom mic close
to the mouth, as is the practice with hand-held microphones.
Voice clarity is best when the mic is about 1/4 inch away and
slightly off center from the lips. Turn the volume control on
the headset, all the way up (clockwise).
On the EAI unit, set both the intercom volume (VOL) control
and squelch (SQ) control to full clockwise position.
Now turn vehicle power on. Then turn the EAI power switch to
“ON”. Verify that you can now hear yourself in your headset.
Verify also that you can hear all the other headsets and that
they can hear you. If everything is OK, skip to the “PTT Test” on
page 8. Otherwise, if something is not working right, see the
following troubleshooting guide to find and fix the problem
before going on with the installation:
No Intercom In Any Of The Headsets:
1. Make sure the EAI power switch and VOLume and SQuelch
controls are set as above.
2. Make sure the vehicle power is on.
3. Check in-line fuse in EAI Radio 1/ Power Interface Cable.
4. Check power connection - red wire.
5. Check ground connection - green wire.
6. Check for short or open on headphone wire (Blue wire on
the Headset Jack and PTT Switch Cable). The problem could
be anywhere along the blue wire connection between the
headset jacks and the EAI unit.
Intercom In Some Headsets But Not In Others:
1. Make sure that EAI switch and controls are set as above.
2. Make sure that neither of the PTT buttons are pressed.
3. Make sure that neither of the PTT wires (white / red or
white / blue) are shorted to ground.
4. Check specific “bad” headset jack wiring for:
a) Microphone wire (jack ring terminal) open or shorted
to ground.
b) Headphone wire (jack tip wire) open or shorted to
ground.
c) Incorrect wiring - wires switched either at the jack or
at the point where the hookup wire connects to the
Headset Jack and PTT Switch Cable.
Loud Squeal In The Headsets All The Time:
1. First make sure all headset plugs are plugged in all the way
and that no part of any headset jack is physically touching
any metal.
2. Check headset jack wiring at all jacks. For example, incorrect wiring such as reversing the jack tip and ring wires will
cause a squeal.
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Page 8
3. Check for open headset jack barrel connection (black wire).
The open could be anywhere along the black wire connection between the jack and the EAI unit.
4. Check for a microphone line (white / black, white / orange,
or tan wires) shorted to the headphone line (blue wire). The
short could be at one of the headset jacks or in the wiring
between the unit and a jack.
Note that for 2 and 3 above, it will only squeal if a headset
is actually plugged into the specific jack that is wired incorrectly.
PTT Test:
If all above is good, make sure all headsets are plugged into
their respective jacks. Put on the Engineer’s (driver) headset
and position the microphone as usual. Press the Engineer’s
PTT switch. While continuing to hold down the switch, talk
into the mic and verify that you can still hear yourself. Also,
while holding down the PTT switch, verify that none of the
other head set microphones are active. Release the PTT
switch.
Now put on the Captain’s headset, position the microphone,
and press the Captain’s PTT switch. Verify that only Captain’s
head set microphone is active as his switch is held down.
If the system has a jack and PTT wired up at the vehicles pump
panel, unplug the headset from the drivers position and plug
it into the pump panels jack. Press and hold down the pump
panel PTT switch. Verify that only the pump panel headset
microphone is active.
If all works fine, skip down to “Electrical Noise Test” on this
page. If anything does not work as above, you have one of
three possible PTT switch wiring errors:
1. PTT line (white / red or white / blue wires) open or not
connected between a PTT switch and the EAI unit.
2. Open or missing return line (black wire) to a PTT switch.
3. Reversed PTT lines. The Engineers PTT line connected to
the Captain’s PTT switch and visa versa.
Electrical Noise Test:
The last thing to do before the radios are hooked up to the
unit is a simple noise test to verify system wiring as well as
vehicle electrical system integrity.
1. Unplug all intercom headsets except for the drivers.
2. Make sure all the EAI panel controls and switches are set
as in “System Setup” on page 6.
3. Start the vehicles engine and let it idle a bit. This is a stationary test - the vehicle should not be moving and should be
in “PARK” or “NEUTRAL” with brakes set.
4. Close all vehicle windows and doors to eliminate as much
background noise as possible.
5. Turn on as much vehicle electrical equipment as possible.
This usually means all lights and strobes. Do not turn on
sirens or horns.
6. Put on the driver’s headset, position the mic, and make sure
the headset volume control is set to maximum.
7. With the vehicle still in “PARK” or “NEUTRAL” and brakes set,
slowly increase the vehicle engine rpm from idle to about
1500 RPM and back again. While doing this, listen for any
whine or hum in the headsets. Except for some possible
engine background noise being picked up from the headset microphone you should not hear any “Electrical” whine
or hum in the headset.
8. Shut off the vehicle engine as well as the lights, strobes,
etc. If, while the engine was running, there was no electrical
noise, skip down to “Radio Hook Up” on page 9. If you did
hear electrical noise, use the following to track down the
problem:
Turn the vehicle power off and disconnect the EAI ground
connection (green wire) from ground. Turn on the vehicle
power (engine off ), put on the driver’s headset and see if
the intercom part of the EAI unit is working.
If You Can Hear Yourself In The Headset:
1. Then the EAI intercom return wire (black) is incorrectly
grounded to the vehicle chassis. Look for:
a) A headset jack barrel touching the vehicle chassis. Most
common when a headset jack is mounted directly into
the vehicle’s panel without using the supplied insulating washers or incorrectly installing the washers.
b) The black wire pinched or cut and shorting to the vehi-
cle chassis. This can be anywhere along the intercom
wiring as the black wire goes to all head set jacks and
PTT switches.
2. Once the problem has been found and fixed, again make
sure that the intercom now does not work with the green
wire disconnected. You could have the black wire grounded
in more than one spot.
3. The next step is to reconnect the green wire and do the
electrical noise test again to assure that you have fixed all
possible noise problems.
If You Cannot Hear Yourself In The Headset:
The intercom wiring is correct, but excessive electrical noise
from the vehicle’s power system is affecting the EAI unit
operation. This noise is getting into the unit on the EAI power
wires (red and green). There are basically two types of power
line electrical noise sources:
1. Noise generated directly by the vehicle’s electrical/charging
system - most commonly known as alternator whine. This
is only present when the vehicle’s engine is running and
recognized by the fact that the pitch or frequency of the
whine changes directly with the change in engine rpm.
(Higher frequency at higher engine rpm’s and lower frequency at lower rpm’s.)
The preferred way to solve this type of problem is to have
the vehicle’s electrical / charging system serviced. The most
common cause of this type of noise is bad diodes in the
vehicle’s alternator. Other possible causes are: bad vehicle
voltage regulator; bad alternator or battery cable connections; missing or bad engine or alternator grounding
straps.
If servicing the vehicle’s charging system is impracti-
cal, installing a good alternator whine power line filter
8
Page 9
between the vehicle power and the EAI red wire will usually accomplish the same thing. Do not use the type of filter
that installs on or near the alternator. NOTE: This solution
should not be considered a permanent fix. Vehicle charging
system problems of this type will eventually cause other
equipment failure as well as shorten the life of the vehicle’s
batteries.
2. The other type of noise is that generated by equipment
that uses the vehicle’s power. This type of noise is usually
constant and does not vary with engine rpm. It does, however, go away completely if the offending equipment is
shut off or disconnected. Electrical motors in fans or light
bars with rotating lights are two common examples.
Several things can be done to rectify this type of electrical
noise:
a) Find a better (less noisy) vehicle power source for the EAI
unit. Move the EAI red wire to another power buss. Try
not to use a power buss that also runs electrical motors
such as fans or light bars with rotating lights.
b) Move the EAI ground connection (green wire) to
another ground point on the vehicle.
c) Install an electrical noise filter on the power line going
to the equipment causing the noise. Contact the company that makes the offending equipment for a recommendation on the type of filter to use.
If something does not work as described, go back over the
wiring and correct before going on. If all is well, you can
tighten all headset jacks and secure all jack box covers
with the supplied hardware. Also, tighten and secure all PTT
switches. On the EAI unit, turn down the intercom VOLume
control to approximately 1/3 position.
V. RADIO HOOK UP
The connection of the EAI unit to the vehicle’s radio(s) should
be done by someone familiar with the radio(s) such as your
radio installer. Refer to the EAI Wiring Diagram -Figure 4 on
page 6 for EAI-S4 or EAI-S6 units or for EAI-D4 or EAI-D6 see
Figure 5 on page 7. Only the radio functions are shown for
the radio end of the EAI Radio Interface Cable. Because the
connector(s) used by radio manufacturers varies widely, you
will have to consult the radio manual or manufacturer for
the connector(s) and pin assignments used. Sigtronics has
extensive radio interface experience and can assist with any
question you might have concerning this or any other aspect
of the EAI system. See our installation hot line number located
on the last page of this manual.
Using the radio manuals and the EAI Wiring Diagram, identify the correct signal wires or connector pins to attach the
respective EAI wires. For most radios, these connections are at
the back of the radio or radio control head. For some radios,
the only place to connect the MIC HI and LO and PTT HI and
LO wires is to the hand-held microphone connector.* It is best
to wire in such a way that the radio hand microphone can
still be used as normal. Make sure that you do not physically
tie the EAI MIC LO and SPEAKER LO wires to the same pin on
the radio, even if they are tied together inside the radio. As
in the headset wiring, the connections between the EAI and
radios should be soldered and insulated for reliability. Do not
use crimp type splices.
Use a good quality electrical tape or heat shrink tubing to
cover the soldered connections.
* For the more popular radios of this type Sigtronics manufactures plug in “Y” adapters to make these connections easy.
Contact your Sigtronics dealer for pricing and availability.
For dual radio units (EAI-D4 or EAI-D6), hook up Radio 1 first
and test before moving on to Radio 2.
Connect the six wires from the Radio 1 / Power Interface
Cable to the appropriate connections on the vehicle’s radio.
Once that is done you will need to adjust the Radio 1 Transmit
Mic Level.
Radio transmit mic level adjustment for the radio (or both
radios for EAI-D4 and EAI-D6) is provided through a hole (or
holes) on the side of the Radio Adapter unit. The adjustment(s)
sets the microphone audio level going to the radio(s) during
transmit. The radio transmit mic level adjustment(s) will need
to be initially set to your particular radio(s). The level(s) once
set, should never need adjustment again unless the type of
radio(s) used are changed. The following simple procedures
take you through the adjustment of the mic level(s).
Radio Transmit Mic Level Adjustment can be made with
a small, flat blade screwdriver. Clockwise rotation increases
the output level to the radio. Counter-clockwise rotation
decreases it. The basic adjustment concept is simple. You
will be setting the level and clarity of outgoing radio transmissions through the EAI unit headsets, to match or exceed
that of transmissions using the radio’s standard hand microphone. To do this, you will need to transmit and receive on the
vehicle’s radio to a remote station. Arrange to have someone
nearby with a radio compatible to the radio you are using
with the EAI. Then
1. Set the EAI ON / OFF switch to the “ON” position. Plug a
headset into the Captain’s jack. Make sure that the volume
control on the headset is turned up to full. It is not necessary to connect the other headsets (or Radio 2 on EAI-D4 or
EAI-D6 units) for this adjustment. On dual radio units (EAID4 or EAI-D6), set RADIO 1/ RADIO 2 switch to “RADIO 1”
and the AUTO / BOTH switch to “AUTO”.
2. Set the headset aside for a moment. With the radio’s hand
mic, transmit as normal, to the remote station. Transmit
long enough so that the receiving station can get “calibrated” to your transmission (voice) level.
3. Put on the Captain’s headset and position the headset
microphone as normal. Verify radio reception. If OK, use
Captain’s PTT to transmit to your receiving party. If receiving station reports weak transmission, use the screwdriver
to turn the RADIO TRANSMIT MIC LEVEL clockwise a small
amount. If they report garbled, broken, or noisy transmissions, turn the RADIO TRANSMIT MIC LEVEL counterclockwise a small amount. Repeat as necessary until the
receiving party reports that transmissions through the EAI
sound as good or better then when using the radio hand
microphone. That’s all there is to it!
Once the mic level is set also check radio operation with the
9
Page 10
vehicles engine running. If radio reception and transmission
through the EAI unit is fine, for EAI-S4 or EAI-S6 units this com-
pletes the installation. Skip down to the “System Operation”
section on page 11. If everything is OK for EAI-D4 or EAI-D6
units skip down to the “Radio 2 Hook Up” section on page
11. If something does not work correctly, check the following
trouble shooting guide:
RADIO TROUBLESHOOTING GUIDE
NOTE: For dual radio units (EAI-D4 or EAI-D6) it is far easier to
troubleshoot with only one radio connected to the Sigtronics
at a time.
First determine if the trouble occurs with the vehicle engine
running.
Vehicle Engine Off:
1. Can’t hear radio in headset:
a) Turn up radio volume at the radio as normal. Make sure
however, you are not picking up the radio through the
headset mics by briefly turning down (counter-clockwise) the intercom VOLume control all the way.
b) Check violet wire (SPEAKER HI and LO) connections from
the EAI to the radio.
c) For EAI-D4 or EAI-D6 units, make sure that RADIO 1/
RADIO 2 switch is set to the radio you want to hear.
d) Some radios do not have sufficient speaker audio to be
heard on a standard EAI system. For such radios a minor
modification can be done to the Radio Adapter unit to
increase the level (by approximately 300%). Refer to
Figure 6 below. Using small piece of hook up wire and
a soldering iron, jumper across the pads as indicated on
the solder side of the Radio Adapter unit circuit board.
For EAI-S4 or EAI-S6 units jumper across the “A” pads. To
increase the audio for RADIO 1 of a EAI-D4 or EAI-D6
unit, also jumper across the “A” pads. To increase the
audio of RADIO 2 on a EAI-D4 or EAI-D6, jumper across
the “B” pads.
FIGURE 6
A
2. Can’t talk to dispatch (transmit) on radio through the head
set:
a) Check the connections between EAI Radio Adapter unit
and the radio. Both white wires (PTT HI and LO) and the
Brown and Black wires (MIC HI and LO).
b) Check the Radio Transmit Mic Level adjustment.
c) If the EAI is connected to a Midland radio a Sigtronics
Mic Level Amplifier might be required to boost the
transmit level. Contact your Sigtronics dealer for details.
B
d) For EAI-D4 or EAI-D6 units, make sure the RADIO 1/
RADIO 2 switch is set to the radio you want to transmit
on.
Vehicle Engine On:
1. Electrical noise (alternator whine) in headsets when receiving on radio, or
Dispatch reports that they hear electrical noise (alternator
whine) when transmitting from vehicle through the headsets.
First make sure that the problem is only related to the radio
hook up. Make sure that you did the “Electrical Noise Test”
for the intercom (without the radios connected) on page 8
and fixed any problems there before you go further. If OK
then:
Check all six radio interface wires between the EAI unit and
the radio - MIC HI, MIC LO, PTT HI, PTT LO, SPEAKER HI, and
LO. Make sure that you have the correct pin numbers for
the radio you are hooking to. Make sure that MIC LO and
SPEAKER LO are not physically tied to the same pin on the
radio; even if they are tied together inside the radio.
If the wiring is OK, then noise is coming from radio.
Possible bad radio wiring, (Check radio power and ground-
connections for loose or corroded connections) or
Excessive noise is generated directly by the vehicle’s electri-
cal / charging system – most commonly known as alternator whine. This is only present when the vehicle’s engine
is running and recognized by the fact that the pitch or
frequency of the whine changes directly with the change
in engine rpm.
The preferred way to solve this type of problem is to have
the vehicle’s electrical / charging system serviced. The most
common cause of this type of noise is bad diodes in the
vehicles alternator. Other possible causes are: bad vehicle
voltage regulator; bad alternator or battery cable connections; missing or bad engine or alternator grounding
straps.
If servicing the vehicle’s charging system is impractical,
installing a good alternator whine power line filter in-line
with the radio power wire(s) will usually accomplish the
same thing. All radio power wires will have to be filtered.
Some radios have more than one wire that hooks to vehicle
power. Contact the radio manufacturer for a recommendation on the best filter for the particular radio. NOTE: This
solution should not be considered a permanent fix. Vehicle
charging system problems of this type will eventually
cause other equipment failure as well as shorten the life
of the vehicle’s batteries.
2. Dispatch says too much background noise or unclear or
weak transmissions.
a) Check to see if a radio hand mic on the vehicle is also
active or ‘live” when transmitting through the EAI unit.
Check this while not wearing a headset and by talking
directly into the radio hand mic and pressing either EAI
PTT switches. Do not press the PTT button on the hand
mic itself. If dispatch can hear you loud and clear, then
10
Page 11
the background noise pick up is coming from this active
hand mic. If you have this type of hand mic then it is best
to contact the radio manufacturer for instructions on a
possible microphone modifica-tion to fix the problem.
Some radio manufacturers can supply a compatible
microphone that does not have this problem.
b) Adjust the EAI Radio Transmit Mic Level Adjustment. If
the mic level is set too low, you will get reports of weak
transmissions. If the mic level is too high, you will get
reports of noisy or garbled transmissions. See “Radio
Transmit Mic Level Adjustment” on page 9.
Radio 2 Hook Up:
Plug in J4 of the Radio 2 Interface Cable into P4 of the Radio
Adapter unit. (This cable has a six pin connector.) Using the
radio manual and Figure 5 on page 7, connect the six wires
to the appropriate connections on the vehicle’s radio. Once
that is done you will need to adjust the Radio 2 Transmit Mic
Level.
The Radio 2 Transmit Mic Level Adjustment is the right one
of the two located on the Radio Adapter unit. The adjustment
procedure is very similar to that of the Radio 1 Transmit Mic
Level adjustment. Arrange to have someone nearby with a
radio compatible with your Radio 2. Then, proceed as follows:
1. Set the EAI ON / OFF switch to the “ON” position. Again,
Plug in a headset into Captain’s jack. Make sure that the
volume control on the headset is turned up to full. (Radio
1 and the other headsets are not needed for this adjustment.) Set the RADIO 1/ RADIO 2 switch to “RADIO 2”
and the AUTO / BOTH switch to “AUTO”.
2. Set the headset aside for a moment. With the radio’s hand
mic, transmit as normal, to the remote station. Transmit
long enough so that the receiving station can get “calibrated” to your transmission (voice) level.
3. Put on the Captain’s headset and position the headset
microphone as normal. Verify Radio 2 reception. If OK, use
Captain’s PTT to transmit to your receiving party. If receiving station reports weak transmission, use the screwdriver
to turn the RADIO 2 TRANSMIT MIC LEVEL clockwise a
small amount. If they report garbled, broken, or noisy transmissions, turn the RADIO 2 TRANSMIT MIC LEVEL counterclockwise a small amount. Repeat as necessary until the
receiving party reports that transmissions through the EAI
sound as good or better then when using the radio hand
microphone.
If Radio 2 does not operate as it should, use the “Radio Trouble
shooting Guide” on page 10 to find and fix the problem. This
completes the EAI installation.
SYSTEM OPERATION
The following describes how to use the EAI System as well as
adjust the EAI controls. It also explains exactly how the EAI
unit operates. This will allow you to easily set all unit functions to your specific needs. If you are not familiar with the
EAI operation, perform the next few steps while the vehicle
is not in motion.
HEADSETS
Put on the headset(s) and position the boom mike close to
the mouth, as is the practice with a hand-held mike. For best
voice clarity, the headset microphone must be positioned to
one side of the mouth and 1/4 inch from the lips. Turn the
volume control on the headset ear cup to maximum. Turn
down for individual hearing needs if necessary only after
intercom and radio volumes have been set correctly. (see
below)
Intercom operation and adjustment can be performed by
the following procedure:
1. Set the ON / OFF switch to the “ON” position.
2. Turn the intercom SQuelch control to the maximum
clockwise position. For best system performance set the
intercom VOLume control as low as possible. On most
systems this will be approximately between 1/4 to 1/3
open. Note: the intercom volume control only adjusts the
volume of conversation between the headsets inside the
vehicle. It does not affect the level at which you hear the
dispatch radio. (see Radio Volume below) You should now
hear yourself and others on the intercom.
3. To adjust the Intercom SQuelch for voice activated operation (VOX), it is helpful to have some background noise
(truck engine or ...). Turn intercom SQuelch control all the
way counter-clockwise. Now, without speaking, rotate the
SQuelch control clockwise until you hear the background
noise in your headset. Next, rotate it counterclockwise in
small amounts until the background noise disappears.
Finally, make small adjustments until your voice triggers
the unit at comfortable speaking levels. This procedure
is necessary because the squelch is a “Fast-on, Slow-off’
system.
When you speak, your voice will be heard in the headsets
but the sound will cut off about a second after you stop
speaking. Minor readjustment of the Squelch may be necessary if the background noise level changes significantly
(engine idling to cruise power with siren on).
RADIO OPERATION
With the EAI System, your radio(s) are heard through the
headsets as well. Adjust the volume level of the dispatch
radio(s) in the headsets with the volume control on the
radio as normal. Note that the radio volume does not effect
the intercom volume and visa versa.
Transmitting (talking to dispatch) from the selected headset
positions is possible on a one-at-a-time basis. For a typical EAI
installation the Captain or Engineer positions can transmit
at any time simply by pressing their PTT switch. The Crew
positions cannot transmit on the radios. When one position
transmits, several things take place automatically:
• All headset microphones, except for the transmitting position, are muted.
• The selected radio is put into transmit mode.
• The headset microphone audio (your voice) is sent to the
selected radio.
11
Page 12
• Sidetone is generated and sent to your headphones.*
* Sidetone is a portion of the transmitted voice signal sent
back into your headset so that you can hear what you are
saying while transmitting. The intercom VOLume control
adjusts the volume level of the sidetone that you hear in
your headset. The other headsets will also hear the transmission sidetone. Of course, when the PTT switch is released,
(stop transmitting) all functions return to normal, instantly
and automatically.
For Dual Radio Units - EAI-D4 and EAI-D6:
The operation of the dual radio EAI units are identical to
that of the single radio units except for the addition of radio
selection:
Radio Selection of both Radio 1 and Radio 2 radios are provided by two switches.
1. RADIO 1/ RADIO 2 (TALK) determines the radio you wish
to transmit on.
2. AUTO / BOTH (LISTEN) selects which radio(s) you receive
or hear in your headset.
a) “ AUTO” position allows you to hear the radio that the
RADIO 1 / RADIO 2 switch is set to.
b) “ BOTH” position permits you to hear both the radios at
Ever y Sig tronics product has bee n carefully inspec ted b efore shipment. We g uarantee to corre ct any defect caused by fau lty
material or wo rkmanship free of charge to the user who origina lly purchased the pro duc t for a perio d of two years from the
original pu rchase date. Our obligati on assumed under this guarantee is limited to the replacin g of any par t or pa rts which
prove to our s atisfaction, upon examination to have b een defective, and which h ave not been mis used or carelessly handled.
The com plete unit m ust be retur ned to our factory, transporta tion c harges prepaid. We rese rve the ri ght to decli ne responsibi lit y where r epairs or replace ments have been made or attemp ted by others. N o other guarantee, written or verbal, on our
product s is author ized by us.
Repairs required due to abuse, misuse, damage o r normal ser vice beyond the warranty pe rio d will be subj ect to normal ser vice charges.
To expedite factory s ervice work, contact Sigtronics Service Departm ent an d explain the problem . All corres pondence relative to service work shou ld inclu de model and ser ial number. Frequently p roblems can be resolved by phon e. The Sigtronics
numb er is located below.
Sigtronics Installation Hot Line Number:
igtronics
S
1-800-367-0977 ext. 8
M-F 8:00 am to 4:30 pm Pacific Time
www.sigtronics.com
®
10-7-2010 EAI_INST_Rev_G.pdf
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