OPERATING RULES

TM 11-5820-890-10-8

OPERATING RULES

The following rules apply to the operation of the RCU in conjunction

with a SINCGARS radio. They are made necessary by the manner in

which the two components work together. It is important that they be

followed to preclude operational problems.

Ensure the RCU is turned ON before setting the radio FCTN to

REM (otherwise data will be lost in the radio).

COMSEC keys in the radio cannot be cleared from the RCU, only

at the radio.

The RCU display will show "OPEN" whenever the connecting field

wire is disconnected or cut, or when the companion radio FCTN is

set to other than REM. If the connecting field wire is disconnected

or cut, the radio automatically changes FCTN to STBY.

When the RCU FCTN is set to STBY, the radio FCTN will change to

that position after about 15 seconds.

Radio battery life condition cannot be set from the RCU, only at the

radio.

ICOM fill of the radio cannot be done remotely, only at the radio.

If vehicular radio uses a Control Monitor, it must be disconnected

before the RCU can be employed.

The normal operating position of RCU FCTN switch is SQ ON.

A "FAIL 9" message resulting from self-testing the RCU normally

indicates that the test was run in PT; change COMSEC to CT and

re-run the test. If "FAIL 9" appears after running test in CT see

unit maintenance.

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