TM 55-1510-215-10
(5) Kilohertz selector. Tunes transceiver in
(3) PLAIN indicator.
Illuminates when the
50-kHz, as indicated by the fourth frequency indicator.
PLAIN/CIPHER switch is in the PLAIN position.
(6) Mode selector.
Determines operating
(4) PLAIN/CIPHER switch. Controls unciphered
mode.
or ciphered communications.
(a) OFF. Turns set off.
(a) PLAIN.
Permits
unciphered
communications on the FM liaison set.
(b) T/R.
Provides for transceiver
operation of frequency displayed on frequency indicator.
(b) CIPHER.
Permits
ciphered
communications on the FM liaison set.
(c) RETRAN.
Not
used
in
this
installation.
(5) RE-X/REG
switch.
Controls
retransmission, or cipher/normal communications.
(d) HOME. Provides for operation in the
homing mode. May also be operated as a transceiver on
(a) RE-X.
Permits retransmission of
channels indicated on frequency indicator.
ciphered communications at a distant location.
(7) VOL control. Adjusts volume.
(b) REG.
Permits normal cipher or
plain communications.
(8) SQUELCH switch. Controls squelch.
NOTE
(a) DIS.
Disables receiver squelch
circuit.
Do not place the ZEROIZE switch in
the ON position unless a crash or
(b) CARR.
Activates receiver squelch
capture is imminent.
circuits.
(6) ZEROIZE switch.
Normally in OFF
(c) TONE. Not used in this installation.
position.
Placed in ON position during emergency
situations to neutralize and make inoperative the
b. Operating Procedures. Refer to Voice Security
associated cipher equipment.
System operating procedures.
(7) CIPHER indicator. Illuminates when the
3-8. Voice Security System (TSEC/KY-28) (If installed).
PLAIN/CIPHER switch is in the CIPHER position.
a. Description. The voice security system is used in
c. Operating Procedures for FM Liaison Set and
conjunction with the FM liaison set to provide secure
Voice Security System.
(ciphered), two-way voice communications (fig. 3-3).
Power for the voice security system is fed through the 50-
NOTE
ampere AVIONICS NO. 1 and AVIONICS NO. 2 circuit
breakers on the copilot's circuit breaker panel. The voice
Disregard the operating procedures
security system is protected by a 10-ampere circuit
involving
the
voice
security
breaker, placarded FM, located on the copilot's subpanel.
(CIPHONY) control-indicator if this
unit is not installed.
b. Controls and Functions.
NOTE
(1) POWER ON switch. Turns set on or off.
The
audio
discriminators
will
NOTE
automatically
interrupt
the
FM
receiver audio
at a given position
Switch must be in the ON position for
whenever the
UHF, VHF, or HF
FM liaison operations in either the
transmitter is
keyed from that
plain or cipher mode.
position.
(2) POWER ON indicator. Illuminates when
(1) Turn-on procedure. POWER ON switch
the POWER ON switch is placed in the up (on) position.
(CIPHONY control-indicator) - ON.
3-4 Change 5
