Sigtronics SPCC-2 Communication Controllers

Sigtronics SPCC-2 Communication Controllers
Sigtronics SPCC-2 Communication Controllers
Models SPCC-2, SPCC-2+2, and SPCC-2+2T
The Sigtronics Portable Communications Controller
(SPCC) provides a pilot/observer “mission team”
with the ability to transmit and receive on multiple
transceivers simultaneously; talk to each other via a
voice activated (VOX) intercom; and monitor a third
audio source. All these features, plus its portability,
make it ideal for the airborne or the ground mission
Typical Radio Configurations: Use with your
aircraft radios (permanently installed or hand-held
models) and an additional “FM” transceiver. A typical
“FM” radio transceiver would be: business band,
police, ham, CB, flight phone, hand-held aircraft,
marine, etc. (Some of these are actually AM radios,
however they can be used).
Dual Audio Panel capability allows each headset
position to select which radios to transmit and
S igtronics ®
receive on - independent of the other headset. Each
headset position has dual volume controls, one for
radio reception, and the other for their intercom
volume level.
Voice Activated Intercom feature allows “handsfree” communication between headsets connected
to the SPCC. Start speaking and the intercom
instantly turns on to relay your message clearly to
the other headset. Stop talking and it turns off to
reduce background noise.
Auxiliary Input lets you monitor a third audio
source, such as a police scanner, music source, etc.
Portable design gives flexibility and eliminates
expensive installation costs. Especially useful
to small departments that rent or lease. Or if a
scheduled aircraft is down, the SPCC can be used
in an alternate aircraft.
Specialists in “SOUND” Management
178 East Arrow Highway, San Dimas, CA 91773 ( 909 ) 305-9399
unbeatable are:
Fail-Safe Bypass Switch allows the pilot to operate
the aircraft radios even if the unit is turned off.
Automatic Sidetone Generation lets the pilot and
copilot hear what the other is transmitting over the
Separate Transmitter Microphone Gain
Adjustments adjust the aircraft radio and the FM
Excellent RF Immunity guarantees clean, clear
Power Requirements: A standard cigarette lighter
socket (11 to 34 VDC) or a battery pack.
Standardized to general aviation headsets and
portable push-to-talk switches. (The unit can also
be wired into permanently installed PTT switches).
Helicopter headsets will also work with the unit if
headset plug adapters are used.
•Airborne Law Enforcement - Small police
departments to large organizations like the FBI.
ON / BYPASS - Power Switch - In “ON” position;
supplies power to all SPCC circuits. In “BYPASS”
position; disables all unit functions, and connects
pilot directly to the aircraft radios. A fail-safe feature!
VOL - Intercom Volume - Adjusts intercom volume
SQ - Intercom Squelch - Adjusts VOX operation of
the intercom for variations in headset microphones
and background noise levels.
XMIT SELECT -Transmit Select - Used to select
which radio to transmit on.
BOTH / OFF / AUTO - Receive Select - Used to select
which radio is heard. In “BOTH” position, you hear
both aircraft and FM radios. In “OFF” position, you
do not hear either radio. In “AUTO” position, only the
radio selected by the XMIT SELECT switch is heard.
AUX / OFF -Auxiliary Select - Turns the auxiliary
input source on or off.
REC VOL - Receive Volume - A general control used
to set the volume level of the aircraft radio(s), FM
radio, and the auxiliary monitor input.
A/C RADIO MIC GAIN ADJ - Aircraft Radio
Microphone Gain Adjustment - Sets the transmit
mic audio level for the aircraft radio(s).
•Civil Air Patrol/Coast Guard -Air search and
rescue operations.
FM RADIO MIC GAIN ADJ - FM Radio Microphone
Gain Adjustment - Sets the transmit mic audio level
for FM radio.
•Medevac Helicopters - Medical emergency
• Airborne Fire Control
• Forestry Departments
•Wild Life Organizations - Survey and tracking
• TV News Crews
• Airborne Traffic Reporters
•Ground Operations requiring more than one
•Additional aircraft VHF radio capability -Add an
inexpensive hand-held aircraft radio as a second
radio without installation costs.
The SPCC requires six simple connections to put it
into operation. The power cord, the aircraft radio,
the FM radio, the auxiliary audio input source
(optional), the push-to-talk switches, and the
headsets must all be connected for the system to
work as designed. But do not fear, Sigtronics has
simplified the connection process, so it will just
take a few moments. Refer to the SPCC connection
drawing Figure 1 on page 3.
1.Power Cord: The four foot power cord with LED
Power Indicator is designed to plug directly into a
standard cigarette lighter socket. The LED indicator
will be on if power is available, it will be off if no
power or reversed socket wiring. Note: The LED
shows power available, not SPCC On or Off. The
SPCC will run on 11-34 VDC, so it automatically
adjusts to 12 or 24 volt aircraft. The SPCC can
Page 2
Hand Mic
Cigarette Lighter or
Portable Battery Pack
LED Power
FM Radio
Interface Cable
FM Radio
Interface Jack
* Portable
Transmit Switch
A/C Radio
Mic Adjust
Aux. Audio
Input Jack
FM Radio
Mic Adjust
Mic Plug
Transmit Plug
* The female jack on portable
push-to-talk switch is not used.
Headphone Plug
also be powered by an auxiliary battery pack, if
2.Aircraft Radio: The mic and headphone cords
on the unit are designed to plug into the mic
and headphone jacks in the panel of the aircraft.
If the aircraft does not have either one of these
jacks, they can be installed by any qualified
avionics technician. If you plan to use the SPCC in
a helicopter, please contact Sigtronics for advise
on adapting the general aviation plugs to the
helicopter jacks.
3.FM Radio: An interface cable is needed to connect
the SPCC to the FM radio. On one end of the
cable will be a five pin connector to plug into the
jack on the top of the SPCC. On the other end
will be whatever is required by your FM radio.
Since virtually any radio can be used and there
is little standardization among manufacturers,
no one cable will work for all radio transceivers.
Therefore, the FM radio interface cable will have
to be fabricated for your particular radio. This
cable can be supplied to you by Sigtronics or
made up by your radio technician. If you decide to
purchase a completed interface cable, Sigtronics
Mic Plug
* Portable
Transmit Switch
Transmit Plug
Headphone Plug
has an extensive cable making facility and can
provide you with one at minimum cost. We will
need to know what length cable you require and
the manufacturer and model number of the radio
you wish to use.
If you would rather have your radio technician
make the cable, the FM radio interface cable
connector pin assignments and some typical cable
wiring examples are located on page 7. A five pin
connector plug is supplied with each SPCC unit for
this purpose. You will also need the radio mating
connector and connection schematic or hook-up
drawing for your particular FM radio. These can
usually be obtained from the radio manufacturer.
4.Auxiliary Radio: If you are using an auxiliary
radio, then a simple interface cable is also needed
to connect the SPCC to the auxiliary audio input
source. The SPCC accepts a standard 1/8” monaural
mini plug.
5.Push-to-Talk Switches: In order for pilot and
observer to transmit on their selected radios,
they will each need a push-to-talk (PTT) switch.
The SPCC is compatible with all standard general
aviation type portable push-to-talk switches. The
Page 3
male plug on the PTT switches plug directly into
the XMIT SW jacks of the SPCC unit. If your PTT
switches also have a female jack, it is not used. The
pilot should strap the switch end of his portable
PTT switch to the yoke or stick of the aircraft.
The observer’s PTT can similarly be strapped to
the co-pilot controls or operated as a hand-held
switch. Various types of push-to-talk switches are
available from Sigtronics, including one that does
not have the female jack.
If you already have permanently wired push-totalk switches in the aircraft, and wish to use them
with the SPCC instead of the portable type, then
wiring modifications will have to be made to the
aircraft. Again, your avionics technician should be
able to do this for you.
6.Headset Hookup: All standard general aviation
headsets are compatible with the SPCC unit.
Helicopter type headsets can also be used if
adapter cables are used. (Sigtronics manufactures
cables that adapt the helicopter plugs to general
aviation plugs).
Plug the microphone and headphone plugs on
the headsets into the jacks labeled MIC and HDPH,
on the front panel of the SPCC. Put on the headset,
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” away
and slightly off center from the lips. Turn headset
volume control(s), if any, all the way up.
The following System Check-Out will provide you
with a “personalized” system. Perform the next
few steps while on the ground to assure that all
functions on the unit and radios are set to your
personal hearing and speaking comfort.
CAUTION - As is standard practice with all aircraft
equipment, be sure that the radio(s) and the SPCC
are turned OFF when you start up the aircraft engine.
1.To assure that the aircraft radios, and pilot’s
headset and PTT switch are connected and
functioning properly, put ON/BYPASS switch into
“BYPASS” position. Then turn on the aircraft radios,
and verify that the pilot can hear the radios and
can transmit using his push-to-talk switch and
headset. All other intercom functions should be
inoperable in the BYPASS mode.
2.Intercom operation and adjustment can be
performed by the following procedure:
A.First set the ON/BYPASS switch to the “ON”
position and turn both REC VOL controls all
the way down (counterclockwise).
B.Turn both intercom volume controls to the 9
o’clock position and both squelch controls all
the way up (clockwise). Notice the intercom is
now continually activated and you should be
able to talk between headsets.
C.To adjust the intercom squelch controls for voice
activated operation (VOX), it is helpful to have
some background noise present. It may also
be necessary to turn up the intercom volume
controls. Turn both intercom squelch controls
all the way counterclockwise. Now, without
speaking, rotate one of the squelch controls
clockwise until you hear the background
noise in your headset. Next, using that same
control, rotate counterclockwise small,
incremental amounts until the background
noise disappears. (This procedure is necessary
because the squelch is a “fast on, slow off”
system). That squelch control is now set.
D.Adjust the other intercom squelch control
similarly by turning it clockwise until you hear
background noise. Rotate counterclockwise
incremental amounts until the background
noise disappears.
Small adjustments may be necessary if aircraft
background noise changes significantly - such
as from idle to full power.
3.Radio Selection of both the aircraft and the FM
radios is provided by two switches.
A.XMIT SELECT determines the radio you wish to
transmit on.
B.AUTO/OFF/BOTH selects which radios you
receive in your headset.
i.“AUTO” position allows you to hear the radio
that the XMIT SELECT switch is set to.
ii.“OFF” prevents you from hearing either
iii.“BOTH” position permits you to hear both
the aircraft radio(s) and the FM radio at the
same time.
4.The AUXliary audio source is selected by the AUX/
Page 4
OFF switch. In the “AUX” position, you can hear it,
and in the “OFF” position you cannot.
5.Receive Volume Controls (REC VOL) are general
volume controls, meant to provide overall listening
level for all three radios simultaneously - A/C,
FM, and AUX. Finite volume adjustments of any
individual radio should be done by altering the
radio volume control at the radio itself.
Once the radios are selected, pilot or observer can
transmit at any time simply by pressing their PTT
switch. When one position transmits, several things
take place automatically to the transmitting side of
the SPCC:
•The intercom between the two positions is turned
•The Auxiliary audio, if selected, is muted.
•The receive audio of the radio not selected by the
XMIT SELECT switch is muted, regardless of the
position of the AUTO/OFF/BOTH switch.
•The selected radio is put into transmit mode.
•The headset microphone audio (your voice) is sent
to the selected transmitter.
Sidetone is generated and sent to your
* 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
RECeive VOLume control adjusts the volume level
of the sidetone that you hear in your headset. If
the AUTO/OFF/BOTH switch is in the “OFF” position
however, you will not hear this sidetone.
The non-transmitting side is not affected (except for
intercom) when the other side transmits. The nontransmitting side can monitor the transmissions of
the other side by simply selecting the same radio on
his side of the SPCC. Of course, when the PTT switch
is released, (stop transmitting) all functions return
to normal, instantly and automatically.
Simultaneous Transmit is the most attractive
and powerful feature of the SPCC. Both pilot and
observer can transmit at the same time - either on
separate radios or on the same radio transmitter!
When on different radios, the pilot and observer
will not interfere with each other’s communications.
For example, the pilot can talk to air traffic control
while the observer talks on the FM radio to the
ground crew, or vice versa. On the other hand, they
can also transmit on the same radio transmitter. If,
for example, the observer is talking on one of the
radios, the pilot can jump right in and add to the
conversation simply by pressing his PTT switch. Both
voices will be heard by the receiving station.
NOTE: Only the aircraft radios and the FM radio
can be transmitted on. The AUXiliary input is for
listening only. It can be used for listening to a police
scanner, monitoring the audio portion of a video
camera, listening to background music, and many
other possibilities.
Transmit microphone gain adjustments for both
the FM and the aircraft radios are provided through
two small holes on the top of the SPCC unit. These
adjustments set the microphone audio level going
to the radios during transmit. Adjustment should be
made only if the outgoing radio transmissions are
reported as weak or garbled. The Aircraft Radio Mic
Gain Adjustment is set at the factory for standard
aircraft radios and should not need any adjustment.
The FM Radio Mic Gain Adjustment, however, will
more than likely need to be initially set to your
particular FM radio. This level, once set, should never
need adjustment again unless, of course, the type
of FM radio used is changed. The following simple
procedures take you through the adjustment of the
FM and A/C mic gain levels. If desired, a qualified
radio technician can do this for you.
FM Radio Mic Gain Adjustment can be made
through the hole to the right of the FM radio
interface connector with a small, flat bladed
screwdriver. The basic adjustment concept is simple.
You will be setting the level and clarity of outgoing
transmissions of the FM radio, when it is hooked
up through the SPCC, to match or exceed that of
transmissions on the radio when it is not connected
to the SPCC. To do this, you will need to transmit and
receive on the FM radio to a remote station. Arrange
to have someone nearby with a radio compatible to
the FM radio you are using with the SPCC. Then . . .
1.Set the ON/BYPASS switch to the “BYPASS”
position and connect the SPCC up to power, as
normal. Plug in the observer’s PTT switch and
Page 5
headset. Do not connect the FM radio to the SPCC
at this time. (It is not necessary to connect the
A/C radios or the pilot’s headset or PTT switch for
this adjustment.) Set the observer’s XMIT SELECT
switch to “FM”, the AUTO/OFF/BOTH switch to
“AUTO”, and the AUX switch to “OFF”.
2.Set the SPCC aside for a moment. With the FM
radio disconnected from the SPCC, transmit as
normal, on the FM radio, to the remote station.
Transmit long enough so that the receiving station
can get “calibrated” to your transmission (voice)
3.Connect the FM radio to the SPCC as normal with
the FM interface cable. Put on the observer’s
headset and turn the SPCC “ON”. Verify FM radio
reception. If OK, use observer’s PTT to transmit to
your receiving party. If receiving station reports
weak transmission, use the screwdriver to turn the
FM MIKE GAIN ADJ clockwise a small amount. If
they report garbled or broken transmissions, turn
the FM MIKE GAIN ADJ counterclockwise a small
amount. Repeat as necessary until the receiving
party reports that transmissions through the SPCC
sound as good or better then when the FM radio
is used separate from the SPCC. That’s all there is
to it!
The A/C Radio Mic Gain Adjustment is located to
the left of the FM radio interface connector. Again,
the A/C Mic Gain Adjustment, in most cases, will not
have to be changed from its original factory setting.
If however, your aircraft radio transmissions through
the SPCC are reported as weak or garbled, you will
need to reset this level. The adjustment procedure
is similar to that of the FM mic gain adjustment
above. You can, however, use the “BYPASS” mode
of the SPCC to aid in the adjustment. Arrange to
have someone with an aircraft radio nearby with
whom you can transmit and receive. Then, proceed
as follows:
1.Set the ON/BYPASS switch to the “BYPASS”
position and connect the unit as normal to power
and aircraft radios. Plug in the pilot’s headset and
PTT switch into the jacks on the left side of the
SPCC. (The FM radio and observer’s headsets and
PTT switches are not needed for this adjustment.)
On the pilot’s side of the SPCC, set the XMIT
SELECT switch to the “A/C” position, the AUTO/
OFF/BOTH switch to “AUTO”, and the AUX/OFF
switch to “OFF”.
2.Put on the pilot’s headset. Transmit and receive
to your nearby station, using the pilot’s PTT
switch and headset, as described in the Initial
System Check-Out section on page 8. Verify good
transmission and reception. In this mode you are
bypassing the SPCC and verifying the clarity of the
aircraft radios.
3.If radios check out OK, then turn the ON/BYPASS
switch to the “ON” position. Verify aircraft radio
reception. If OK, use the pilot’s PTT to transmit to
your receiving party. If the receiving station reports
weak transmissions, use the screwdriver to turn the
A/C MIKE GAIN ADJ clockwise a small amount. If
they report garbled or broken transmissions, turn
the A/C MIKE GAIN ADJ counterclockwise a small
amount. Repeat as necessary until the receiving
party reports that transmissions with the SPCC
turned “ON” sound as good as that when the ON/
BYPASS switch is “BYPASS” mode.
Page 6
Male five pin connector shown from solder side:
FM Radio Interface Cable Connector
Pin Assignment
Mic audio output to FM radio
Receive audio input from FM radio
FM radio ground
Transmit key output to FM radio (Normally
2,5 open relay contacts closed during FM radio
Pin #
Mic Audio Input
Headphone Audio
Transmit Key Input
Pin #
1 2 4 3 5
Figure 4 is similar to Figure 3 but is used for radios
requiring a low level mic input such as marine type
1 2 4 3 5
Figure 3 shows the most common of such cables
with its “high level mic input” and standard “ground
to key” interface. This cable will work with most
standard police, fire, and business band radios as
well as aircraft type radios.
The following are some examples of possible wiring
schemes for the FM interface cable. Only the FM
radio functions are shown for the FM radio end of
the 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) used and pin assignments for your
particular FM radio. Also, Sigtronics has extensive
radio interface experience and can assist in any
question you might have concerning this or any
other aspect of the SPCC. Of course, Sigtronics
can build a FM interface cable for you to your
specifications, if desired.
33K *
Mic Audio Input
1K *
Headphone Audio
Transmit Key Input
* Use 1/8 or 1/4 watt resistors
Pin #
1 2 3 4 5
Figure 5 shows typical cable wiring for radios that
sense the presence of mic current to transmit. Most
ICOM hand-held radios are set-up this way.
Headphone Audio
Transmit Key Input
Page 7
The +2 option allows for one or two additional headset positions to be added to the standard SPCC for
intercom. This is ideal for training or if you need
additional spotters or observers along on your missions. A small remote satellite unit is provided that
connects to the main SPCC unit. This satellite unit
comes standard with two sets of headset jacks and
a four foot cable so that it can be placed in the back
seat of the aircraft for convenience. The satellite unit
is also detachable for those times you only need
two positions. As well as full VOX intercom, the back
two headsets also hear the radio(s) selected by the
front observer’s position. Similarly, the radio receive
and intercom volume and squelch controls on the
observer’s panel also control the corresponding
levels for the back two positions. These back two
positions cannot transmit on any of the radios and
their microphones are silenced whenever the observer presses his PTT switch to transmit. They will,
however, hear what the observer is transmitting. All
other functions for the pilot and observer positions
operate just as with non +2 units.
Every Sigtronics’ Product has been carefully
inspected before shipment. We guarantee to correct
any defect caused by faulty material or workmanship
free of charge to the user who originally purchased
the product per the enclosed warranty card. Our
obligation assumed under this guarantee is limited
to the replacing of any part or parts which prove to
our satisfaction, upon examination to have been
defective, and which have not been misused or
carelessly handled. The complete unit must be
returned to our factory, transportation charges
prepaid. We reserve the right to decline responsibility
where repairs or replacements have been made or
attempted by others. No other guarantee, written
or verbal, on our products is authorized by us.
The +2T option operates just like +2 option (See
above) except for one exception. The back two positions can transmit. They will only transmit on the
radio that is selected on the observers side of the
SPCC. Two additional jacks are provided on the satellite unit for portable PTT switches. One for each
back position.
Repairs required due to abuse, misuse, damage or
normal service beyond the warranty period will be
subject to normal service charges.
To expedite factory service work, write Sigtronics’
Service Department and explain the problem. All
correspondence relative to service work should
include model and serial number. Frequently
problems can be resolved by phone. Should you
wish to call, our number is (909) 305-9399.
Input Voltage: 11-34 VDC
Nominal Current: 0.07 Amps
Maximum Current: 0.15 Amps
Weight: 22 oz.
Size: 3.75 x 6.25 x 2.5 inches
A/C Interface Cord length: 4 feet each
178 East Arrow Highway
San Dimas, CA 91773
Phone: 909-305-9399
FAX: 909-305-9499
Page 8
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF