Sigtronics UltraSound Emergency Intercom System
INSTALLATION AND OPERATING INSTRUCTIONS
Models US-12S and US-12D
US-12S
US-12D
INTRODUCTION
ATTENTION INSTALLER: To assure a trouble free installation, please read these entire instructions through once
before beginning.
The Sigtronics UltraSound Emergency Intercom System,
when used with Sigtronics noise attenuating headsets provides the emergency apparatus crew with clear, hands free,
voice activated (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.
Specialists in “SOUND” Management
Voice Activated Intercom (VOX) feature allows “hands
free” communication between headsets connected to the
UltraSound 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 Twelve Headset Positions can be connected to the
UltraSound unit models US-12S and US-12D. 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 head- set into his jack while driving.
He then unplugs and plugs into the pump panel when he
arrives on scene.
Made in the U.S.A.
178 East Arrow Highway, San Dimas, CA 91773 ( 909 ) 305-9399
Headphone Output: The UltraSound system is designed to
easily drive twelve or more 300 to 1000 ohm headsets. Noise
attenuating, full cushion headsets, such as the Sigtronics SE-8,
or SE-48 are recommended for best results. The UltraSound
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 is design to accommodate virtually any type of communication radio. Adjustments for radio
receive level and transmit microphone level are provided to
perfectly match the UltraSound system to your particular
radio.
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
(i.e. SE-8, SE-48, SE-18).
Model Differences: The US-12S is used in applications requiring up to twelve persons at one time on intercom. Four of the
twelve have radio transmit capability. The US-12S is designed
for use with a single vehicle radio. The US-12D is identical
to the US-12S but can accommodate two separate vehicle
radios.
CONTROL FUNCTIONS
VOLUME — Intercom Volume — Adjusts intercom volume
level. Does not affect radio volume.
SQUELCH — Intercom Squelch — Adjusts VOX operation of
the intercom for variations in background noise levels.
RADIO 1/RADIO 2 (TALK) — Transmit Select (US-12D units
only) — Used to select which radio to talk on — Radio 1 or
Radio 2.
AUTO/BOTH (LISTEN) — Receive Select (US-12D 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 selec ted by the R ADIO 1/RADIO 2
switch is heard.
RADIO MIC TRANSMIT GAIN — Located on the back of the
unit — Sets the transmit mic audio level for the radio(s).
RADIO VOLUME — Located on the back of the unit — Sets the
range of receive audio from the radio(s).
ULTRASOUND INSTALLATION
Installation Overview:
Sigtronics has simplified the installation process, to assure
perfect operation. Refer to the UltraSound Wiring Diagram
(for US-12S see Figure 4 on page 5; for US-12D see Figure 5
on page 6). 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.
Standard Equipment Included
Besides the Intercom unit, each UltraSound system comes
complete with the following:
US-12S US-12D
Intercom Mounting Bracket 1 1
Headset Jack Box and Cover
with Pre-mounted Headset Jack 4 4
with Pre-mounted Headset Jack
& Splash Cover 1 1
PTT Switch Pre mounted
in PTT Box and Cover 3 3
Headset Hooks 4 4
Jack Box Cover Screws 16 16
Jack Box and Bracket Mounting Screws 28 28
Wire Grommets 8 8
Jack Insulator Washer, Flat 5 5
Jack Insulator Washer, Shoulder 5 5
4 ft. Headset Jack & PTT Cable 12 Pin 1 1
4 ft. Headset Jack & PTT Cable 9 Pin 1 1
4 ft. Radio 1 Interface Cable 1 1
4 ft. Radio 2 Interface Cable N/A 1
6 conductor hook-up wire (Roll) 1 1
Installation of the Sigtronics UltraSound System is a four step
process:
I. Mount the intercom unit.
(INTERCOM CHASSIS INSTALLATION)
II. Install the headset jacks and PTT switches.
(HEADSET JACK AND PTT SWITCH INSTALLATION)
III. Wire the jacks and PTT switches.
(HEADSET JACK AND PTT SWITCH WIRING)
IV. Wire the radio(s). (RADIO HOOK UP)
I. INTERCOM CHASSIS INSTALLATION
Intercom Placement:
There are a few factors to consider when selecting a mounting location for the UltraSound Intercom chassis:
1. The unit should be placed in such a way that the controls
on the front of the unit 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 dash
mounted. It can be mounted on top of the dash or hang
below the dash or vehicle ceiling. The mounting bracket
is adjustable to allow for various mounting angles.
3. The location selected requires a minimum area of 2-5/16”
high by 7-7/8” wide by 4” deep. Verify that the intercom unit
and cables will not interfere with the normal operation of
any vehicle controls or the operation of vehicle compartment doors.
Mounting Intercom Unit: See Figure 1
1. Once the location is selected, remove the mounting
bracket from the intercom unit by unscrewing the two
large knobs. Be careful not to lose any of the four ratchet
washers.
2. Set the mounting bracket in the selected area and mount
with four of the hex head self drilling screws. For most
2
applications* these screws can be installed with no predrilling. Just power in the screws with a standard electric
driver with a 5/16” hex bit. * No pre drilling required for aluminum 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.
FIGURE 1
UltraSound
SQUELCH
INTERCOM
SEE TEXT
VOLUME
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 additional 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.
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-
FIGURE 2
TAN
INTERCOM PTT SWITCH
OPEN JUMP SEAT WIRING DIAGRAM
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 combination of both.
TIPRING
BARREL
HEADSET JACK
3
BLUE
BLACK
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 (i.e. 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 UltraSound 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:
Set the jack box on the mounting surface in the selected area
and mount with two of the hex head self drilling screws. For
most 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 aluminum and steel. 1/8” inch pilot
hole will still be required with some stainless steels.
For most installations the wiring for the headset jack will
come out the back of the jack box. A hole is already provided
in the jack box for this purpose. Of course, you will also have
to drill a similar hole into the vehicle. Use a 5/16 inch drill for
this.
Alternately, the wire can come out of the side of the jack box
if desired. You will have to drill the hole where required. Use
a 5/16 inch drill. Rubber wire grommets are provided for the
wire going through the jack box hole.
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 0.195” 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. The Jacks have 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 Driver or Officer positions to transmit on the
radio, they will each need a Push-To-Talk (PTT) 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.
SHOULDER
INSULATING
WASHER
TIP
BARREL
RING
HEADSET JACK
FLAT
INSULATING
WASHER
VEHICLE
PANEL
FLAT
METAL
WASHER
NUT – OR – SPLASH COVER AND NUT
FIGURE 3
The PTT switches can be mounted in the blue ptt mounting
boxes or directly into a panel. If using the ptt boxes, set the
box on the mounting surface in the selected area and mount
with two of the hex head self drilling screws. For most 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 aluminum and steel.
1/8” inch pilot hole will still be required with some stainless steels.
If mounting the PTT switches directly into a panel the switch
is mounted from the front and the panel can have a maximum thickness of 3/16 of an inch.
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. The nut requires a 7/8”
wrench
III. HEADSET JACK AND PTT SWITCH WIRING
The wiring of the headset jacks and PTTs is straight forward.
In general, the 4 foot 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. The
cable J1 for the four radio transmit positions has a 12 pin connector with 12 wires. Before going on, plug in J1 of the cable
into P1 on the Intercom unit. The cable for the eight other
headset positions (J4) has a 9 pin connector with 9 wires. Plug
this J4 connector into P4 on the Intercom unit.
Flexible four conductor hook-up wire is provided with each
system to connect each headset jack and PTT switch to
the UltraSound unit’s Headset Jack and PTT Switch Cables.
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 UltraSound Wiring Diagram (for US-12S see Figure
4, for US-12D see Figure 5) for the exact wiring information.
The connections between the Headset Jack and PTT Switch
Cables 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
4
FIGURE 4
SPEAKER HI (J2-2) VIOLET
SPEAKER LO
123
PTT HI
RADIO 1
PTT LO
MIC HI
MIC LO
(J2-3) VIOLET
(J2-5) WHITE
(J2-6) WHITE
(J2-1) BROWN
(J2-4) BLACK
NOTE 1
NOTE 1
NOTE 2
NOTE 2
+11 to +16
VOLTS DC
FUSE
(1 AMP)
(J1-7) RED (J1-12) GREEN
J2
P2
J1
P1
CHASSIS
GROUND
(J1-2) WHITE/RED
(J1-1) WHITE/BLACK
(J1-4) BLACK
(J1-3) BLUE
(J1-10) WHITE/BLUE
(J1-11) WHITE/ORANGE
(J1-10) WHITE/BLUE
(J1-11) WHITE/ORANGE
(J1-9) YELLOW
(J1-8) WHITE/BROWN
PTT SWITCH
RING
HEADSET JACK
DRIVER
PTT SWITCH
RING
HEADSET JACK
CREW #3
TIP
BARREL
TIP
BARREL
PTT SWITCH
RING
HEADSET JACK
OFFICER
PTT SWITCH
RING
HEADSET JACK
PUMP PANEL
TIP
BARREL
TIP
BARREL
UltraSound
SQUELCH
INTERCOM
VOLUME
INTERCOM UNIT
US-12S (SINGLE RADIO) WIRING DIAGRAM
NOTES:
1) CONNECT EITHER VIOLET WIRE TO THE RADIO SPEAKER HI OUTPUT.
CONNECT THE REMAINING VIOLET WIRE TO SPEAKER LO.
2) CONNECT EITHER WHITE WIRE TO THE RADIO PUSH-TO-TALK (PTT) KEY LINE INPUT.
CONNECT THE REMAINING WHITE WIRE TO THE PTT KEY LINE RETURN (PTT LO).
(J1-6) WHITE/GREEN
PTT SWITCH
(J1-5) ORANGE
P4
J4
(J4-1) TAN
RING
TIP
RING
HEADSET JACK
CREW #4
TIP
BARREL
BARREL
HEADSET JACK
(J4-2) TAN
CREW #5
RING
TIP
BARREL
HEADSET JACK
(J4-3) TAN
RING
TIP
CREW #6
BARREL
HEADSET JACK
(J4-4) TAN
CREW #7
RING
TIP
BARREL
HEADSET JACK
(J4-5) TAN
RING
TIP
CREW #8
BARREL
HEADSET JACK
(J4-6) TAN
CREW #9
RING
TIP
BARREL
HEADSET JACK
(J4-7) TAN
RING
TIP
CREW #10
BARREL
HEADSET JACK
(J4-8) TAN
CREW #11
RING
TIP
BARREL
HEADSET JACK
CREW #12
(J4-9) BLACK
5
FIGURE 5
SPEAKER HI
SPEAKER LO
123
PTT HI
RADIO 2
RADIO 1
PTT LO
MIC HI
MIC LO
SPEAKER HI (J2-2) VIOLET
SPEAKER LO
123
PTT HI
PTT LO
MIC HI
MIC LO
(J3-2) VIOLET
(J3-3) VIOLET
(J3-5) WHITE
(J3-6) WHITE
(J3-1) BROWN
(J3-4) BLACK
(J2-3) VIOLET
(J2-5) WHITE
(J2-6) WHITE
(J2-1) BROWN
(J2-4) BLACK
NOTE 1
NOTE 1
NOTE 2
NOTE 2
NOTE 1
NOTE 1
NOTE 2
NOTE 2
J2
P2
FUSE
(1 AMP)
(J1-7) RED
+11 to +16
VOLTS DC
J1
P1
CHASSIS
GROUND
(J1-12) GREEN
J3
P3
(J1-2) WHITE/RED
(J1-1) WHITE/BLACK
(J1-4) BLACK
(J1-3) BLUE
(J1-10) WHITE/BLUE
(J1-11) WHITE/ORANGE
(J1-10) WHITE/BLUE
(J1-11) WHITE/ORANGE
(J1-9) YELLOW
(J1-8) WHITE/BROWN
PTT SWITCH
RING
HEADSET JACK
DRIVER
PTT SWITCH
RING
HEADSET JACK
CREW #3
TIP
BARREL
TIP
BARREL
PTT SWITCH
RING
HEADSET JACK
OFFICER
PTT SWITCH
RING
HEADSET JACK
PUMP PANEL
TIP
BARREL
TIP
BARREL
RADIO 1
AUTO
RADIO
UltraSound
SQUELCH
TALK
RADIO 2
INTERCOM
LISTEN
BOTH
VOLUME
INTERCOM UNIT
US-12D (DUAL RADIO) WIRING DIAGRAM
NOTES:
1) CONNECT EITHER VIOLET WIRE TO THE RADIO SPEAKER HI OUTPUT.
CONNECT THE REMAINING VIOLET WIRE TO SPEAKER LO.
2) CONNECT EITHER WHITE WIRE TO THE RADIO PUSH-TO-TALK (PTT) KEY LINE INPUT.
CONNECT THE REMAINING WHITE WIRE TO THE PTT KEY LINE RETURN (PTT LO).
(J1-6) WHITE/GREEN
PTT SWITCH
(J1-5) ORANGE
RING
TIP
BARREL
P4
J4
(J4-1) TAN
RING
TIP
HEADSET JACK
CREW #4
BARREL
HEADSET JACK
(J4-2) TAN
CREW #5
RING
TIP
BARREL
HEADSET JACK
(J4-3) TAN
RING
TIP
CREW #6
BARREL
HEADSET JACK
(J4-4) TAN
CREW #7
RING
TIP
BARREL
HEADSET JACK
(J4-5) TAN
RING
TIP
CREW #8
BARREL
HEADSET JACK
(J4-6) TAN
CREW #9
RING
TIP
BARREL
HEADSET JACK
(J4-7) TAN
RING
TIP
CREW #10
BARREL
HEADSET JACK
(J4-8) TAN
CREW #11
RING
TIP
BARREL
HEADSET JACK
CREW #12
(J4-9) BLACK
6
and PTT switches will also have to be soldered. See Figure 3
on page 4 for jack terminal identification.
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 UltraSound unit will run on 11-16 VDC. CAUTION:
UltraSound units are designed for negative ground vehicles
only. They 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 UltraSound power wire. The power for the
UltraSound unit comes in on the red and green wires on the
Headset Jack and PTT Switch Cable.
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. 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 UltraSound unit, set both the intercom VOLUME con-
trol and SQUELCH control to full clockwise position.
Now turn vehicle power 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 UltraSound VOLUME and SQUELCH controls are set to full clockwise position.
2. Make sure the vehicle power is on.
3. Check the in-line fuse in the UltraSound Headset Jack and
PTT switch Cable.
4. Check the power connection - red wire.
5. Check the ground connection - green wire.
6. Check for a short or open on the 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 UltraSound unit.
INTERCOM IN SOME HEADSETS BUT NOT IN OTHERS:
1. Make sure that UltraSound controls are set as above.
2. Make sure that none of the PTT buttons are pressed.
3. Make sure that none of the PTT wires (white/red, white/
blue, yellow, or white/green if applicable) 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.
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 UltraSound unit.
4. Check for a microphone line (white/black, white/orange,
white/brown, 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.
7
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 Driver’s headset and position the microphone as usual. Press the Driver’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 headset
microphones are active. Release the PTT switch.
Now put on the Officer’s headset, position the microphone,
and press the Officer’s PTT switch. Verify that only the Officer’s
headset 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, white/blue, yellow, or white/green
wires) open or not connected between a PTT switch and
the UltraSound unit.
2. Open or missing return line (black wire) to a PTT switch.
3. Reversed PTT lines. The Drivers PTT line connected to the
Officer’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 UltraSound 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 possi-ble.
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 8. If you did
hear electrical noise, use the following to track down the
problem:
Turn the vehicle power off and disconnect the UltraSound
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 UltraSound unit is working.
IF YOU CAN HEAR YOURSELF IN THE HEADSET:
1. Then the UltraSound 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 headset 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 UltraSound
unit operation. This noise is getting into the unit on the
UltraSound 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
between the vehicle power and the UltraSound 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.
8
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
UltraSound unit. Move the UltraSound 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 UltraSound 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 UltraSound unit, turn down the intercom
VOLUME control to approximately the 10 o’clock position.
IV. RADIO HOOK UP
The connection of the UltraSound 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 UltraSound Wiring Diagram
- Figure 4 for US-12S units or for US-12D see Figure 5. Only the
radio functions are shown for the radio end of the UltraSound
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 UltraSound system.
See our installation hot line number located on the last page
of this manual.
First plug J2 of the Radio 1 Interface Cable into P2 of the
Intercom. Then using the radio manuals and the UltraSound
Wiring Diagram, identify the correct signal wires or connector pins to attach the respective UltraSound 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 UltraSound 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 UltraSound 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 manu-
factures plug in “Y” adapters to make these connections easy.
Contact your Sigtronics dealer for pricing and availability.
For dual radio units (US-12D), hook up Radio 1 first and test
before moving on to Radio 2.
Connect the six wires from the Radio 1 Interface Cable to the
appropriate connections on the vehicle’s radio. Once that is
done you will need to set the RADIO 1 VOLUME switch on the
back of the UltraSound unit. See Figure 6 on this page. This
switch and the vehicles radio volume control set how loud
you hear the vehicles radio in the headsets. For most applications the default setting of “LO” (up for Radio 1) is fine. If the
vehicles radio volume has to be turned up too high to hear it
in the headsets, set this switch to the “HI” position (down for
Radio 1). Otherwise leave it in the “LO” position. The switch can
be set with a pen or small flat blade screwdriver.
The last step is to set the Radio 1 Microphone Transmit Gain.
Microphone Transmit Gain (labeled MIC XMIT GAIN) adjustment for the radio (or both radios for US-12D) is also provided
on the back of the UltraSound unit. The adjustment(s) sets the
microphone audio level going to the radio(s) during transmit. The Microphone Transmit Gain adjustment(s) will need
to be initially set to your particular radio(s). The gain(s) once
set, should never need adjustment again unless the type of
radio(s) used is changed. The following simple procedures
take you through the adjustment of the Microphone Transmit
Gain(s).
Radio Microphone Transmit Gain Adjustment can be
made with a small, flat blade screwdriver. Referring to Figure
6 above, the gain adjustment is set by two controls - a “HI/LO”
RANGE switch and a rotary “ADJ” control. Set the RADIO 1 MIC
XMIT GAIN RANGE switch to the “LO” position (up for Radio
*On Dual Radio units only. Models US-12D.
RADIO VOLUME switch for Radio 2*
*
RADIO
VOLUME
RADIO VOLUME switch for Radio 1
MIC XMIT GAIN RANGE switch for Radio 2*
MIC XMIT GAIN ADJ for Radio 2*
RADIO 2
HI
MIC
LO
LO
RANGE
HI
RADIO 1
MIC XMIT GAIN RANGE switch for Radio 1
MIC XM IT
XMIT
GAIN A DJ
MIC XMIT GAIN ADJ for Radio 1
FIGURE 6
1). This is the default factory setting. Adjust the “ADJ” control
clockwise to increase the output gain or 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 UltraSound 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 UltraSound. Then . . .
1. Plug a headset into the Officer’s jack. Make sure that the
volume control on the headset is turned up to full. It is not
9
necessary to connect the other headsets (or Radio 2 on US12D units) for this adjustment. On dual radio units (US-12D),
set RADIO 1/ RADIO 2 switch to “RADIO 1” and the AUTO
/ BOTH switch to “AUTO”.
2. Put on the Officer’s headset and position the headset
microphone as normal. Turn the UltraSound VOLUME
con-trol all the way down (counter-clockwise). You should
not be able to hear yourself in the headset.
3. 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.
4. Verify radio reception. If OK, use Officer’s PTT to transmit
to your receiving party. If receiving station reports weak
transmission, use the screwdriver to turn the RADIO 1 MIC
XMIT GAIN ADJ clockwise a small amount. If they report
garbled, broken, or noisy transmissions, turn the RADIO 1
MIC XMIT GAIN ADJ counter-clockwise a small amount.
Repeat as necessary until the receiving party reports that
transmissions through the UltraSound sound as good or
better than when using the radio hand microphone.
5. If the receiving party reports that your transmissions are
still weak with the MIC XMIT GAIN ADJ at the full clockwise
position, then switch the RADIO 1 MIC XMIT GAIN RANGE
switch to the “HI” position (down for Radio 1) and repeat
steps 3 and 4 above. That’s all there is to it!
Once the gain is set, also check radio operation with the
vehicles engine running. If radio reception and transmission
through the UltraSound unit are fine, for US-12S units this
completes the installation. Skip to the “System Operation”
section on page 11. If everything is OK for US-12D units, skip
to the “Radio 2 Hook Up” section on page 11. If something
does not work correctly, check the following troubleshooting guide:
Radio Troubleshooting Guide:
NOTE: For dual radio units (US-12D) it is far easier to trou-
bleshoot with only one radio connected to the Sigtronics
UltraSound unit 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 microphones by briefly turning down (counterclockwise) the intercom VOLUME control all the way.
b) Check violet wire (SPEAKER HI and LO) connections from
the UltraSound to the radio.
c) Set the appropriate RADIO VOLUME switch on the back
of the UltraSound unit to the “HI” position.
d) For US-12D units, make sure that RADIO 1/RADIO
2 switch is set to the radio you want to hear.
2. Can’t talk to dispatch (transmit) on radio through the
headset:
a) Check the connections between UltraSound unit and
the radio. Both white wires (PTT HI and LO) and the
Brown and Black wires (MIC HI and LO).
b) Check the UltraSound Radio Mic Transmit Gain adjust-
ment.
c) For US-12D 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.
a) 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 7 and fixed any problems there before
you go further. If OK then:
b) Check all six radio interface wires between the
UltraSound 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.
c) If the wiring is OK, then noise is coming from radio:
i) Possible bad radio wiring, (Check radio power and
ground connections for loose or corroded connections) or. . .
ii) Excessive noise is 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.
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 inline 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.
10
a) Check to see if a radio hand mic on the vehicle is
also active or “live” when transmitting through the
UltraSound unit. Check this while not wearing a headset and by talking directly into the radio hand mic and
pressing either UltraSound PTT switches. Do not press
the PTT button on the hand mic itself. If dispatch can
hear you loud and clear, then 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
modification to fix the problem. Some radio manufacturers can supply a compatible microphone that does
not have this problem.
b) Adjust the UltraSound Radio Mic Transmit Gain controls.
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
Mic Transmit Gain Adjustment” on page 9.
MIC XMIT GAIN ADJ counter-clockwise a small amount.
Repeat as necessary until the receiving party reports that
transmissions through the UltraSound sound as good or
better then when using the radio hand micro-phone.
5. If the receiving party reports that your transmissions are
still weak with the MIC XMIT GAIN ADJ at the full clockwise position, then switch the RADIO 2 MIC XMIT GAIN
RANGE switch to the “HI” position and repeat steps 3 and
4 above.
If Radio 2 does not operate as it should, use the “Radio Troubleshooting Guide” on page 9 to find and fix the problem. This
completes the UltraSound installation.
HEADSET HOOK INSTRUCTIONS
The enclosed headset hooks are provided at no additional
charge to allow for a convenient way to store the headset.
These strong and durable hooks may be mounted in any location. Two mounting methods seem to be preferred:
Radio 2 Hook Up:
Plug in J3 of the Radio 2 Interface Cable into P3 of the
UltraSound unit. Using the radio manual and Figure 5 on
page 6, connect the six wires to the appropriate connections
on the vehicle’s radio. Once that is done you will need to set
the RADIO 2 VOLUME switch on the back of the UltraSound
unit. See Figure 6 on page 9. For most applications use the
default setting of “LO” (down - which is the reverse of the
Radio 1 switch). If the vehicles radio volume has to be turned
up too high to hear it in the headsets, set this switch to the
“HI” position.
Next, set the Radio 2 Microphone Transmit Gain. The Radio
2 Microphone Transmit Gain Adjustments are the top set
of the two located on the back of the UltraSound unit. The
adjustment procedure is very similar to that of the Radio
1 Mic Transmit Gain adjustment. First set the RADIO 2 MIC
XMIT GAIN RANGE switch to the “LO” position (default setting). NOTE: the HI and LO switch positions for Radio 2 are
upside-down from that of Radio 1. Arrange to have someone
nearby with a radio compatible with your Radio 2. Then, proceed as follows:
1. Again, plug in a headset into Officer’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. Put on the Officer’s headset and position the headset
microphone as normal. Turn the UltraSound VOLUME
control all the way down (counter-clockwise). You should
not be able to hear yourself in the headset.
3. 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.
4. Verify Radio 2 reception. If OK, use Officer’s PTT to trans-mit
to your receiving party. If receiving station reports weak
transmission, use the screwdriver to turn the RADIO 2 MIC
XMIT GAIN ADJ clockwise a small amount. If they report
garbled, broken, or noisy transmissions, turn the RADIO 2
FIGURE 7
a.
1. Top Mounting ( Figure 7-a ). The hooks may be mounted
from the existing headliner screws and hardware, or you
may use the enclosed attaching screws. When used with
an electric driver these screws are self drilling. For most
metals such as aluminum or common steel, they will not
require a pilot hole. For some stainless steels however,
1⁄8” pilot holes will need to be drilled. Attach the right
angle mounting bracket to the hooks with the machine
screws and lock nuts.
2. Side Mounting ( Figure 7-b ). The hooks may be mounted
on the side of the cab with the enclosed attaching screws.
Note: The right angle mounting bracket may be shortened (
one hole removed ) by cutting with any standard hack saw.
This completes the UltraSound installation.
SYSTEM OPERATION
The following describes how to use the UltraSound System as
well as adjust the UltraSound controls. It also explains exactly
how the UltraSound unit operates. This will allow you to easily
set all unit functions to your specific needs. If you are not familiar
with the UltraSound 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
b.
11
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. 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 the 10 o’clock position. 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 Operation below) You should
now hear yourself and others on the intercom.
2. 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 counter-clockwise 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 UltraSound 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
UltraSound installation the Driver, Officer, or Crew #4 positions can transmit at any time simply by pressing their PTT
switch. The other 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.
— 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 transmis-
sion sidetone. Of course, when the PTT switch is released,
(stop transmitting) all functions return to normal, instantly
and automatically.
For Dual Radio Units - US-12D:
The operation of the dual radio UltraSound 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
the same time.
UltraSound Specifications
Input Voltage: 11 - 16 VDC
Nominal Current: 0.10 Amps
Maximum Current: 0.20 Amps
Intercom Unit Size: 1-3/4 “ H x 6 - 1/8” W x 4” D
(Mounting bracket & knobs add 9/16” to
H & 1 - 3/4” to W)
Weight: 15 oz. (not including cables and hard-
ware)
Warranty: Two Years
igtronics
S
®
Sigtronics Installation Hot Line Number:
1-800-367-0977 ext. 8
M-F 8:00 am to 4:30 PM Pacific Time
www.sigtronics.com
2-19-2013 US-12S_D Rev F
12
P/N700125
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