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SIGTRONICS “TRANSCOM” INSTALLATION AND OPERATING INSTRUCTIONS (PERMANENT)
Transcom is a voice actuated aircraft intercom with the capability
for transmitting through the aircraft radio by the mere push of a
button. It was designed for simplicity of use. Three controls are
provided on the front panel. (See Figure 1)
POWER SWITCH — Turns unit on and off.
VOLUME CONTROL — Controls the intercom volume. (The radio
volume is controlled conventionally.)
SQUELCH CONTROL — Controls the threshold of amplier
turn-on. This control is normally used to adjust for variations in
background noise found in different aircraft.
Two Microphone Input Jacks, labeled MIKE, are provided. They
accept the standard aircraft mike plugs (i.e. carbon or amplied
dynamic microphone.)
Two Output Jacks are provided, labeled HDPH which accept the
standard .250” aircraft headphone plug.
Two jacks are provided on the panel, labeled XMIT SW which
accept the standard aircraft .206” mike plugs: found on aircraft
SIGTRONICS TRANSCOM CONNECTION SCHEMATIC
FIGURE 1
FIGURE 2
push-to-talk switches. These are normally not used in the
Permanent TRANSCOM, since provisions are made for hard
wiring the push-to-talk functions to the aircraft. However, they may
be used as an option with portable aircraft push-to -talk switches.
Transmitting from both positions is possible on a one -at- a-time
basis. Each position disables the other while transmitting.
OPERATING INSTRUCTIONS
After the intercom is installed per the instructions above, it is
ready for use. Figure 2 illustrates the connections between the
TRANSCOM and headsets. In addition, push-to-talk switches are
shown in Figure 2 with dashed line for reference only. Portable
push-to-talk switches may be plugged in as shown, if it is not
desired to connect the orange and yellow wires as shown in
Fig.3.
STEP 1 — INTERCOM MODE
A. Turn the power switch on.
B. Set the volume control to a low level.
C. Adjust the squelch control clockwise until background noise
increases or the voice is heard by speaking into mike. Rotate
the squelch counterclockwise until noise diminishes. Then
make small adjustments until the voice triggers the unit on
satisfactorily. Small adjustments may be necessary if the
aircraft background noise changes signicantly, such as from
idle to full power.
STEP 2 — TRANSMIT MODE
When ready to transmit, depress the Transmit Switch and your
voice is automatically transmitted via the aircraft radio.
STEP 3 — RADIO MONITORING
When the unit is connected as shown, radio monitoring is
automatic. The radio monitor circuit is always active, even with
the TRANSCOM Power Switch in the OFF position.
HELPFUL HINTS
Position the boom mike in close proximity to the mouth, as is the
practice with a hand held mike, for best results.
Maintain minimum acceptable volume when using TRANSCOM
– particularly in low noise environments.
A fuse is located within the unit and may be replaced by a qualied
person should the need arise.
The hand held mike may be left plugged into the aircraft mike input
jack and used conventionally. However, the TRANSCOM must
be switched off during transmitting. Radio reception will continue
through the headphone, even with TRANSCOM switched off.
When transmitting the intercom is automatically switched OFF and
your voice is heard via the aircraft radio sidetone return. In cases
where there is no sidetone return, nothing will be heard.
The push-to - talk switch circuit must have less than 5 ohms
resistance for satisfactory operation.
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INSTALLATION INSTRUCTIONS: Please read the following instructions carefully so that you can derive maximum benet from your SIGTRONICS TRANSCOM.
CONN ECTOR
PIN NO.
A. Power Red Aircraft Rad io Circu it Breake r
B. Mike Output Brown Aircraft Mike Input Jac k (Rin g)
C.
D.
E. Audio Input Blue Aircraft H eadphone Jack
F.
H. Ground Black
FUNCTION
Transmit Relay
control
Left Transmit
Switch Input
Right Transmit
Switch Input
WIRE
COLOR
White Aircraft Mike Input Jac k (Tip)
Orange Left Transmit Switc h
Yellow Right Transmit Switch
Aircraft cha ssis or ei ther Input Jack
Ground
GOES TO
CHASSIS INSTALLATION
Your TRANSCOM has been supplied with:
4 mounting grommets,
4 6/32” machine screws,
4 locking nuts
for mounting the intercom case.
1. Remove the 4 corner panel screws from the face panel.
2. Remove the intercom from the case.
3. After selecting a suitable mounting location in the aircraft, bore
four 1/4” holes in the case. (The TRANSCOM may be mounted
by securing to the case front or back sides, or bottom.)
4. Bore a 3/4” hole to provide a means of penetrating the case
with the 7 pin connector and cable. (If the front or rear case
surface is selected for the 3/4” hole, locate the hole toward the
case bottom to minimize interference between the cable and
intercom circuit board.)
5. Insert the 4 grommets into the 1/4” holes.
6. Drill aircraft with same hole pattern as in the intercom case, but
use a No. 27 drill. (Clearance drill for 6/32”)
7. Secure case to the aircraft with screw heads inside the intercom
case. (For circuit board clearance)
Sigtronics Corporation
178 East Arrow Highway
San Dimas, CA 91773
Phone: (909) 305-9399
NOTE:
1. If push-to -talk switch is connected to aircraft mike input jack, it must be
disconnected and connected to the orange wire as shown.
2. Orange wire must correspond to left mike input jack because of opposite
side cancel feature.
WIRING INSTRUCTIONS
Your TRANSCOM has been supplied with:
One 6 inch 7 conductor cable, terminated in a 7 pin connector, One
4 ft. 7 conductor mating cable, for wiring the unit to the aircraft.
The wires are color coded to conform with standard aircraft radio
color coding, where applicable.
Figure 3 is a schematic illustration of the TRANSCOM wiring
connections to be made to the aircraft.
A Table is also presented in Fig. 3 which outlines the connector
pin numbers, along with the function, color and destination of
each wire in the cable. It is important to note that the orange and
yellow wires must be connected to the corresponding push-to-talk
switches as shown, because of the “opposite side disable” feature.
In addition, if the aircraft already has a push- to -talk switch hard
wired to the mike input jack, it must be disconnected from that
mike input jack and connected, as shown in Fig. 3 to the orange
wire. When wiring is completed, tape or otherwise insulate metal
parts on connector plug to prevent their contact with other aircraft
electrical equipment.
NOTE: Care should be taken to verify that the aircraft radio wiring
conforms to the standard color code.
A trimmer pot is provided inside the unit to adjust radio mike input
level. Appropriate adjustments can be made to compensate for
over or under modulation. Clockwise rotation increases mike output
level of intercom to radio.
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