INTERCOM (ICM) OPERATION
This mode of operation allows the RCU operator to communicate with the radio operator without transmitting a signal.
Set RCU FCTN to ICM.
Press CALL button and handset push to talk at the same time. The RCU and radio displays show "CALL" and a
two-tone alarm is heard in the RCU and radio handsets. This alerts radio operator that RCU operator wishes to
communicate. If either display falls to show "CALL", try again. If several attempts have failed, turn In RCU and radio to
Press handset PTT and speak.
When call is complete, reset RCU FCTN switch to SQ ON or other operating position.
The RCU first tests the RCU; then the companion radio (if connected). Always perform self-test before or after a mission.
Refer to the radio receiver transmitter self-test (page 54) as needed. The display must show "GOOD" or "OPEN" at the
end of the self-test ("OPEN" display indicates that the two wire link is cut, disconnected, or the companion radio FCTN
switch is not set to REM.)
Set RCU COMSEC switch to CT and FCTN to TST.
Watch as the displays cycle in the following sequence:
TWO-WIRE CONNECTED TO COMPANION RADIO
"FALL 9" indicates that self-test was done with the COMSEC switch set to r. If "FAIL 9 " is displayed during self-test when
COMSEC switch is set to CT, turn In RCU to unit maintenance. If any other fall display is shown, refer to radio receiver
transmitter self-test. page 54 If you cannot operate RCU due to failure. refer to RCU troubleshooting, page 5-15.