TM 11-5820-890-10-1
l Main Junction Box (Amplifier, Audio Frequency AM-1780/VRC). The main
junction box controls power to the radios and the control boxes. Refer to the
following list for main junctibn box switch settings:
MAIN PWR:
OFF
INIT ONLY
NORM
CKT BKR:
OFF
ON
INT ACCENT: ON
INSTALLATION:
RETRANS
OTHER
INT ONLY
RAD TRANS:
CRD +
CREW
Allows all crewmembers to use PlT for radios.
CDR ONLY Allows commander (only) to use PTT for radios.
LISTENING Does not allow PTT for radios.
SILENCE
Removes all power from the system.
Allows communication between crewmembers.
Supplies power to the mounting adapter or power
supply adapter (power to radios).
Removes power to the control boxes.
Supplies power to the control boxes.
Reduces receive RT audio (intercom audio remains
the same).
Disconnects PTT capability between radios and con-
trol boxes.
Used when main junction box is connected to radios.
Used when main junction box is not connected to ra-
dios.
l Control Box (Control, lntercommunication Set C-2298/VRC). The control box
is used to allow communication between commander and crewmembers. If you
have a different control box (C-2296, C-2297, or C-10456) 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 + LlSTEN)
ALL
YES
YES
INT ONLY
YES
YES
A
YES
YES
C
YES
NO
* Position B is not used with SINCGARS.
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