TM 11-5820-890-10-
OPERATION
RCU operation Is identical to radio operation with a few exceptions. You may:
Load or offset SC frequencies, receive or send an ERF, change modes or functions, change channels, select COMSEC
keys, select PT or CT operation, select data rates, and clear FH data in the radio. The RCU operation is slower than
radio operation. You must wait for for radio signal to reach RCU to continue operation. Otherwise, some keyboard
entries, etc. wont be accepted. Carefully read the following notes, determine what procedure you wish to perform; then
refer to radio operating procedures In Chapter 2.
OPERATIONAL NOTES
The radio and battery warnings and cautions at the front of this manual also apply to the RCU. Read them carefully.
Make sure to perform scheduled PMCS and routine checks as required.
Set radio FCTN switch to REM AFTER turning on RCU. Data will be lost if radio FCTN is set to REM before RCU is
turned on. Use the radio to clear COMSEC keys that are loaded in the radio. If two wire Is cut, disconnected, or radio
FCTN switch is not set to REM, RCU display shows "OPEN". Radio battery life condition must be set at the radio. RCU
battery life condition is set at the RCU. RCU data rates are set at the RCU.
When RCU FCTN is set to STBY , the companion radio also goes to OFF after about 16 seconds. Likewise, If the
two wire Is cut or disconnected, the companion radio will go into OFF
Local fill of SC and FH data must be done with the radio. ERF may be received using the RCU.
It is not possible to clear COMSEC keys from radio at RCU.
Set RCU COMSEC switch to PT when RCU FCTN switch IS set to ICM.
If radio is being controlled by a CM, disconnect CM before using RCU.
4-3