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SIGTRONICS “TRANSCOM” INSTALLATION AND OPERATING INSTRUCTIONS (REMOTE 2 WAY)
HEADPHONE
JACKS
MIKE
2
SQUELCH
CONTROL
VOLUME
CONTROL
SWITCH
MOUNTING
HARDWARE
13 CONDUCTOR
CABLE
2
JACKS
FIGURE 1
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 to operate the unit.
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 amplifier turnon. This control is normally used to adjust for variations in
background noise found in different aircraft.
HARDWARE PROVIDED:
Two Microphone Input Jacks -- They accept the standard aircraft
mike plugs (i.e., carbon or amplified dynamic microphone).
Two Output Jacks -- They accept the standard .250” aircraft
headphone plug.
Transmitting from both positions is possible on a one-at-a-time
basis. Each position disables the other while transmitting.
OPERATING INSTRUCTIONS
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 the noise diminishes. Then
make small adjustments until
SIGTRONICS CORPORATION
178 East Arrow Highway
San Dimas, California 91773
(909) 305-9399
the voice triggers the unit on satisfactorily. Small adjustments may be necessary if the aircraft background
noise changes significantly, 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 in “WIRING
INSTRUCTIONS” radio monitoring is automatic. The
radio monitor circuit is always active, even with the
TRANSCOM Power Switch in the OFF position.
HELPFUL HINTS
1. Position the boom mike in close proximity to the mouth,
as is the practice with a hand held mike, for best results.
2. Maintain minimum acceptable volume when using
TRANSCOM, particularly in low noise environments.
3. 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.
4. 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.
5. 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
PLUG
PIN NO.
10 White/Blue Right Transmit Switch Input Right Transmit Switch
WIRE
COLOR
1 White/Black Left Mike Input
2 White/Red Left Transmit Switch Input Left Transmit Switch 12 No Connection
3 Violet Squelch Control Input
4 Black Ground Aircraft Chassis Ground 14 Blue Radio Headphone Input
5 White
6 Brown Mike Output Ring of Aircraft Mike Input Jack 16 No Connection
7 Red Power Input Radio Circuit Breaker
8 Orange Volume Control Output Volume Control Wiper
9 Yellow Volume Control Output Volume Control Clockwise Pin
FUNCTION CONNECT TO:
Ring Terminal of Intercom Left
Mike Input Jack
Clockwise Pin of Squelch
Control
Transmit Relay Control
Output
Tip Terminal of Aircraft Mike
Input Jack
CHASSIS INSTALLATION
Your TRANSCOM has been supplied with the necessary
PLUG
PIN NO.
11 White/Orange Right Mike Input
13 Gray Headphone Output All Intercom Headphone Jacks
15 No Connection
NOTE: Connect the CCW Pin of the Volume Control to Intercom System Ground.
WIRE
COLOR
Connect the CCW Pin and Wiper of Squelch Control to Intercom System Ground.
Connect one terminal of push-to-talk switch to Aircraft Chassis or Intercom System Ground.
Aircraft Chassis Ground.
Intercom System Ground.
FUNCTION CONNECT TO:
Ring Terminal of Intercom Right
Mike Input Jack
Aircraft Radio Headphone Output
Jack
TABLE 1
Table 1 lists the connector plug pin numbers, the color, function,
and destination of each wire connected to those pins.
hardware to mount the Chassis to the aircraft.
Four grommets are installed in the Chassis bottom, intended for mounting.
Four 6/32” screws with self-locking nuts have been pro-
Connections should be made as shown in Figure 2 and as indicated in Table 1. Sigtronics should be contacted if other means of
connecting the unit are contemplated.
vided for mounting.
NOTE:
1. Remove the four corner panel screws from the unit.
2. Remove the unit from the case.
3. After selecting a suitable mounting location in the aircraft,
drill aircraft with the same hole pattern as in the intercom case.
Use a No. 27 drill (Clearance drill for 6/32”).
4. Secure case to the aircraft with the screw heads inside intercom case for circuit board clearance. (Care should be taken not
to crush the grommets while applying torque to the screws.)
5. Replace the unit in the case and secure.
1. Care should be taken to verify that the aircraft radio wiring
conforms to the standard color code.
2. The Squelch and Volume Control shafts should be cut to
length after installation plan is complete.
3. To avoid ground loop induced noise, the microphone,
volume control and squelch control grounds should be floated and
returned to the unit ground. The unit ground, in turn, should be
carried close to the aircraft mike input jack ground.
4. A small, square, white or gray trimmer potentiometer is
provided inside the unit for adjusting the mike input level to the
WIRING INSTRUCTIONS
Your TRANSCOM has been supplied with four feet of cable
to connect the unit to the aircraft.
Figure 2 illustrates the connection to be made.
radio. In the event of overmodulation or reports of weak transmissions, an appropriate adjustment can be made. Clockwise
rotation of the screwdriver adjustment increases the mike output
level.
REM 1027
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