BATTLE DAMAGE DESCRIPTION

TM11-5830-263-20&P

1.16.

BATTLE DAMAGE DESCRIPTION

Battle damage control in the VIS is made possible by redundant paths in the highway - cable ring

architecture. The system continues to function if there is a single break in any of the cables or the paths

within the crew boxes that carry power, data signals, or analog audio. Special circuitry within the MCS

and each of the FFCS and RIT boxes comes into play if the data signal path is broken. If the MCS does

not sense receipt of the digital data stream at its bottom STATION connector, it recognizes that there is a

break in the path and initiates transmission from the bottom connector to communicate with the

disconnected portion of the ring. (This involves operation of an internal relay that removes a terminating

resistor from the data path and inserts the same signal transmitted at the top station connector.)

The break in the data path is also sensed and accommodated by the digital boxes on either side of the

break. (A dc bias on the two data lines forming the path segment interconnecting adjacent boxes

activates a zener diode circuit that applies terminating resistors to prevent signal reflections from both

sides of the break in the data path.) The system continues to provide communication to all crew stations,

and "ru" is displayed by the MCS to indicate that maintenance is required. (The dc bias voltage of

approximately 20 volts provides a convenient method to verify continuity to connectors within FFCSs and

RlTs during troubleshooting.)

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