TEXT: AN/VIC-1(V) Intercommunications and Radio Controls
  The AN/VIC-1(V) intercommunications system provides tactical crew
  members with facilities for communications with any radio
  connected to the system, as well as facilities for communicating
  with each other.  It includes the AM-1780/VRC and various
  intercommunications controls - C-2296, C-2297, and C-2298.  The
  numbers and types of controls are dependent upon the type of
  vehicle and its operational function.
  Equipment Check List:
  1x AM-1780/VRC Audio Frequency Amplifier; 
   
  Main junction for radio and intercom communications.
  1x C-2299/VRC Radio Set Control;
   
  Used for radio rebroadcasting.
  4x C-2298/VRC Intercommunications Set Control;
   
  Used as a crewmember control box for the AM-1780
  1x C-2296/VRC Intercommunication Set;
   
  Used for outside communications to the radio set and
  with personnel inside vehicle.
  1 or 2x C-2742/VRC Frequency Select Control;
   
  Used for the selection of 10 pre-set radio frequencies.
  2x MT-1029;
   
  Trays used for mounting radios.
  2x MX-6707;
   
   
  AMU, used for antennae loading, automatically finds
  frequency by use of the ant. Control cable hooked up to
  the radio.
  Equipment Descriptions
  AM-1780/VRC Audio Frequency Amplifier
  The AM-1780/VRC amplifies the intercom and radio receiver outputs
  and is the main junction box for a radio installed in a vehicle. 
  It has ten cable receptacles on the top, bottom and sides. 
  Operating controls, and indicator lamp and two pairs of binding
  posts are on the front.
  Technical Specification
  Output Power: 1 watt
  Input Channels: 4
  Input Impedance
   (3 channels) 150 ohms
   (1 channel) 5000 ohms
  Output Impedance: 100 ohms
  Frequency Response: 300 Hz- 3 KHz +- 4 db
  Distortion: 5% max at 600 ohms load
  Power Supply: 255 v dc nominal
  
  Temperature Range: -10 to +55 degrees C
  Height: 14.6 cm
  Width: 24.8 cm
  Depth: 9.5 cm
  Weight: 3.6 kg
  AM-1780/VRC Audio Frequency Amplifier
  Description of Picture and Usage
  Main Power Switch
   
  Three position switch that controls intercom and radio
  system power.
   
  Off: Turns system power off.
  Int Only: Turns on system power for intercom.
  Norm: Turns on system power for radio and intercom.
  Intercom Accent Switch
  Adjusts relative loudness of intercom and radio signals
  Off: Radio and intercom signals have same loudness.
  On: Intercom signals are louder than radio signals.
  Radio Transmission Switch
  Determines which crewmember boxes can control the radios
  CDR + CREW: Commander and crew can control radios.
  CDR Only: Only commanders box can control radios.
   
  Listening Silence: Neither can talk on radio or intercom
  system.  Radio can only be monitored.
  
  Power Indicator
   
  Indicates Power Circuit (CKT) Breaker (BKR) is ON and power
  is applied.
  Power Circuit Breaker Switch
   
  Controls power to 1780 and provides overload protection.
  Audio Input Binding Posts
  N/A
  Line Binding Posts
   
  Connection for field telephones.  Provides communication on
  intercom system only.
  C-2296/VRC Intercommunication Set Control
  This intercom control is mounted outside the vehicle and provides
  communications to the radio set in the vehicle and with personnel
  inside the vehicle.
  The control has a handset, H-207/VRC, connected to the case. 
  Operating controls and a pair of binding posts for connecting
  field telephone lines on the front.
  Technical Specification
  Height: 9.5 cm
  Width: 11.4 cm
  Depth: 9.5 cm
  Weight
   (Incl handset): 2.1 kg
   (Excl handset): 1 kg
    
  C-2296/VRC Intercommunication Set Control
  No Picture Available (Yet) 
  Description and Usage
  Toggle Switch
  Selects either intercom or radio.
  Rad Trans: Send on radio.
  Int: Send on intercom
  Volume Knob
   
  Adjusts the relative volume of either the intercom or radio
  reception.
  Line Binding Posts
   
  Connection for field telephones.  Provides communication on
  intercom system only.
  
  C-2298/VRC Intercommunication Set Control
  The C-2298/VRC provides crew member communications on the radio
  set in the vehicle.  This control unit is usually mounted at the
  crew members’ and commander’s position in the vehicle
  Technical Specification
  Height: 9.5 cm
  Width: 11.4 cm
  Depth: 12.4 cm
  Weight: 1.2 kg
  C-2298/VRC Intercommunication Set Control
  Description and Usage
  Monitor Switch
   
  Selects either intercom or radio signal heard and permits
  control of radio by operator of audio accessory.
   
  ALL: Send and receive on radio and intercom.
   
  A: Send and receive on radio.
   
  INT ONLY: Hear and talk on intercom only.
   
  B: Not used.
  C: For operation of radio in “B” tray only.
  Note: ALL 2298 boxes must be in the same switch position. 
  Volume Control
   
  Adjust audio output to audio accessory.  It will not make
  microphone input any louder.
  
  Connectors for C-2298/VRC
  J803: 
  Connection for headset/helmet.  Longest or yellow
  marked cord connects here.
  J802: 
  Connection for headset/helmet.  Short cord goes here.
  C-2299/VRC Radio Set Control
  The C-2299/VRC is installed in a vehicle when retransmission
  facilities are provided.
  The C-2299/VRC selects the radio set to be controlled by the
  audio accessory in the vehicle, provides switch to retransmit
  mode, and controls audio levels applied to audio accessories. 
  Technical Specification
  None Available at this time.
  C-2299/VRC Radio Set Control
  Description and Usage
  RAD TRANS Switch
   
  Selects radio to be controlled by audio accessory.
   
  Position 1: Selects radio in “A” tray.
  Position 2: Selects radio in “B” tray.
  RETRANS Switch
   
  OFF: Radios work independently of each other
   
  ON: Permits automatic passage control and audio signals
  between radios.
  
  VOLUME Control
   
  Controls audio output of 2299 through receptacles J703, J704
  Connectors for C-2299/VRC
  J703 & J704: 
  Connection for audio accessory to talk, key and
  listen to radios selected by RAD TRANS switch.
   
  Note: When used with 1780 box, the 2298 will be
  used for selecting radios.
  Headset/ Helmet
  The only additional equipment required for internal
  communications is the headset/ helmet.
  Operating Instructions for Internal Communications
  CAUTION: ALWAYS ENSURE THAT COMMS EQUIPMENT IS SHUT OFF BEFORE
  STARTING OR STOPPING THE VEHICLE ENGINE...
  AM-1780/VRC
   
  Step 1. Turn MAIN PWR switch to INT ONLY
   
  Step 2. Turn PWR CKT BKR to ON
   
  Step 3. Turn RADIO TRANS switch to CDR + CREW
  C-2298/VRC
   
  Step 1. Turn MONITOR switch to INT ONLY
   
  Step 2. Ensure all 2298 boxes are on the same setting
  Headset/ Helmet
   
  Step 1. Turn ICS box switch to ICS
   
  Step 2. If you have no communications refer to FAULT FINDING
  chart
  NOTE: IF USING ONLY ONE RADIO IN THE VEHICLE, ENSURE IT IS IN “A”
  TRAY (LEFT HAND TRAY).
  
SOURCE: textdata/thevault/The Morrow Project/Unofficial/The Supply Bunker/New Vehicles/Snippets/AN VIC-1(V) Series Internal Vehicle Communications Guide.pdf