Sigtronics US-12D - Manual (Page 9)

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, how-
ever, 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 com-
pany that makes the offending equipment for a recom-
mendation 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 connec-
tor 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 applica-
tions 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) adjust-
ment 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 trans-
mit. 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
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
RADIO VOLUME switch for Radio 2*
MIC XMIT GAIN RANGE switch for Radio 2*
MIC XMIT GAIN ADJ for Radio 2*
MIC XMIT GAIN ADJ for Radio 1
MIC XMIT GAIN RANGE switch for Radio 1
RADIO VOLUME switch for Radio 1
RADIO
VOLUME LO
HI
RADIO 2
RADIO 1
HI
LO
MIC
XMIT
RANGE
MIC XMIT
GAIN ADJ
*
*On Dual Radio units only. Models US-12D.
FIGURE 6