Figure 1-13.-TSEC/KY-75 remote control unit.
TSEC/KY-75 Remote Control Unit
The TSEC/KY-75 remote control unit (RCU) is
shown in figure 1-13. This unit enables the operator to
operate the security unit without moving from the
NAV/COMM station in the aircraft. The following is an
explanation of the various controls and indicators on the
RCU.
1.
2.
3.
4.
ALARM indicator–This indicator will
illuminate whenever there is an alarm condition
in the security unit.
TSEC/KY-75 RCU switch–This switch is not
used.
PWR/FILL switch–This is a four-position
switch used to select the key and storage
locations for the various codes used.
a
b.
OFF/ZEROIZE–This position will zeroize all
variables stored in the TSEC/KY-75 security
unit. To select this position, the operator must
pull the knob out 1/4 inch and turn it
counterclockwise. This prevents accidental
zeroizing during flight.
1, 2, 3–These positions select a particular key
for the cipher transmission or reception. They
also select the storage area when the key is
loaded into the TSEC/KY-75.
PWR indicator–This indicator will illuminate
white when power is applied to the security unit
5.
6.
and the PWR/FILL switch is not in the
OFF/ZEROIZE position.
SIG CLR switch–This switch is pressed to
enable the till operation if the TSEC/KYK-13 or
TSEC/KOI-18 is attached If a fill device is not
attached pressing this switch will cause the
security unit to preamble.
FILL connector–This connector connects the
filling device to the TSEC/KY-75 security unit
electrically. This enables the operator to load
keys into the security unit.
HF FUNCTIONAL DESCRIPTION
Both radio sets function in the same manner; the
only difference between the two is the peripheral
equipment used. Figure 1-14 shows a system block
diagram.
Receive Function
The RF signal is received by the antenna, coupled
through the coupler and the de-energized
transmit-receive relay in the RF amplifier, and finally to
the receiver transmitter receiver RF input. RF-to-audio
conversion is accomplished in the receiver section using
inputs from the frequency synthesizer. The recovered
audio component is amplified to a power level sufficient
to be used as an audio input to the peripheral equipment.
Transmit Function
During the transmit function, voice or data signals
from the peripheral equipment are switched through the
COMM switching matrix to the USB and LSB transmit
audio inputs to the receiver transmitter. A keying signal
is also applied from the peripheral equipment. For
emergency or maintenance operations, voice and keying
signals can originate at the mic/headset assembly
connected directly to the receiver transmitter.
Figure 1-14.-HF system block diagram.
1-19
