INTERCOM (ICM) OPERATION
This mode of operation allows the RCU operator to communicate with the radio opera-
tor 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 fails to show CALL, try again. If several attempts have failed,
turn in RCU and radio to unit maintenance.
Press handset PTT and speak.
When call is complete, reset RCU FCTN switch to SQ ON or other operating
The RCU first tests the RCU: then the companion radio (if connected). Always per-
form self-test before or after a mission.
Refer to the radio receiver-transmitter self-test (page 5-4) 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
"FAIL 9 indicates that self-test was done with the COMSEC switch set
. If FAIL 9 is displayed during self-test when COMSEC switch
is set to CT, turn in RCU to unit maintenance. If any other fail display
is shown, refer to radio receiver-transmitter self-test. page 5-4. If you
cannot operate RCU due to failure, refer to RCU troubleshooting, page