TM 11-5820-890-10-3
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Main Junction Box (Amplifier, Audio Frequency AM1780/VRC). The main junction box controls power to the radios
and the control boxes. Refer to the following list for main junction box switch settings:
MAIN PWR:
OFF
Removes all power from the system.
INIT ONLY
Allows communication between crewmembers.
NORM
Supplies power to the mounting adapter or power supply adapter (power to radios).
CKT BKR:
OFF
Removes power to the control boxes.
ON
Supplies power to the control boxes.
INT ACCENT:
ON
Reduces receive RT audio (intercom audio remains the same).
INSTALLATION:
RETRANS
Disconnects PTT capability between radios and control boxes.
OTHER
Used when main junction box is connected to radios.
INT ONLY
Used when main junction box is not connected to radios.
RAD TRANS:
CRD +
Allows all crewmembers to use PTT for radios.
CREW
CDR ONLY
Allows commander (only) to use PTT for radios.
LISTENING
Does not allow PTT for radios.
SILENCE
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VIC Control Box (Control, Intercommunication Set C2298/VRC). The control box is used to allow communication
between commander and crewmembers. If you have a different control box (C2296, C2297, or C10456) in the VIC
system that you are using, refer to the appropriate operator's manuals for switch settings. Refer to the following list
for control box switch settings:
VIC CONTROL BOX FUNCTIONS BY SWITCH POSITION:
FUNCTION
POSITIONS*
CDRS
CREW
RADIO "A" (TALK + LISTEN)
ALL, A
YES
YES
RADIO "B" (LISTEN)
ALL, C
YES
YES
INTERCOM (TALK + LISTEN)
ALL
YES
YES
INT ONLY
YES
YES
A
YES
YES
C
YES
NO
* Position B is not used with SINCGARS.
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