TM 1-1520-238-10
3-20
3.8 VOICE SECURITY SYSTEM TSEC/KY-58.
The TSEC/KY-58 (RCU), located in the right console, in-
terfaces with the AN/ARC-186 and AN/ARC-201 radios to
provide secure voice (ciphony) for these radios. The
TSEC/KY-58 receives 28 vdc from the 28 vdc emergency
bus through the KY-28 circuit breaker on the pilot over-
head circuit breaker panel.
Two operating modes are available: PLAIN mode for in-
the-clear voice transmission or reception, and C/RAD 1
(cipher) mode for secure radio transmission or reception.
NOTE
The RCU POWER switch must be set to ON
and the KY-28 circuit breaker must be IN be-
fore AN/ARC-186 or AN/ARC-201 radio
communication (plain or ciphered) is pos-
sible.
3.8.1 Controls and Functions.
Voice security system
controls that require adjustment by the pilot include those
on the Z-AHQ Power Interface Adapter, TSEC/KY-58 (lo-
cated in the aft avionics bay), and the Z-AHP KY-58 RCU
(located in the pilot right-hand console). Each of these de-
vices are shown in figure 3-6. The function of each control
and indicator is described in tables 3-5 through 3-7.
Table 3-5.
Z-AHQ Power Interface Adapter Control and Indicator Functions
Control or Indicator
Function
BBV, DPV, BBN,
DPN 4-position
switch
Set according to type of radio being secured. Set to BBV for pilots VHF FM radio.
PTT button
(push-to-talk)
Clears crypto alarm that occurs upon power up. Alarm can also be cleared by pressing any
push-to-talk switch in the pilot compartment.
FILTER IN/OUT
Selector
Prevents adjacent channel interference when using radios with channel spacing of 25 kHz.
Must be set to IN for pilots AN/ARC-186(V) VHF-FM radio.
REM/LOC Switch
Sets the Z-AHQ to the local mode. Switch returns to REM (remote) position upon release,
but equipment remains in local mode until any PTT is keyed.
