TM 11-5820-890-10-1
SECURE COMMUNICATION. Secure operations may be done in SC or FH modes.
Two radios having the same COMSEC key can communicate in cipher text by setting
the COMSEC switch to CT and selecting the same COMSEC key. A COMSEC key
is a variable used to enable secure communication. Have one or more COMSEC keys
loaded into your RT before a mission if you need to handle secure traffic. You can
then exchange secure voice and data with other RT-1523(C)/U having the same
COMSEC key, The RT CHAN switch selects a COMSEC key. You can keep the same
channel but change the COMSEC key by scrolling. You can also communicate with
other VHF FM radios which are equipped with a KY-57 COMSEC device.
NOTE
When a station in
calls one in CT, the receiving operator
can hear the message and the beeping in the background. This
tells the receiving operator that the sender has COMSEC set to
rather than CT.
Even if you have a COMSEC key loaded, when your radio has
been set to
and is switched to SQ ON, you will hear a
COMSEC alarm. Pressing PTT twice will clear this alarm,
SCROLLING COMSEC KEYS. Use this procedure to change the COMSEC key (you
cannot scroll or change COMSEC key in channel 6), and to keep the same SC fre-
quency, or FH net.
a.
b.
c.
d.
Set RT CHAN to 1, 2, 3, 4, 5.
Press CMSC.
Display shows "TEK n".
Press CHG to change COMSEC
key. Display shows new TEK.
Repeat step c until the COMSEC
key you want Is displayed.
You must press handset
push-to-talk to clear alarm.
* FUNCTION. Refer to the local SOP for authorized use of this function. The * function
may be used in CT and can be changed from OFF to ON by pressing */2; then CHG.
If you are using a RT-1523(C)/U with a device that doesn’t have a * function capabili-
ty, set the RT-1523(C)/U * function to OFF.
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