The KY-75 voice security system is used in conjunction with a HF command set to provide secure (ciphered, two-way voice communications). It was an analog voice device whose voice quality was poor and adjusting it was difficult.
KG-65 is manpack portable.
KG-75 is for shipborne and airborne operation.
This is not an image of the KY-75, only the remote control unit. (Courtesy TM 55-1510-220-10)
DESCRIPTION OF CONTROLS
Refer to above graphic.
1) RMT-LOCAL-SIG CLR switch - Selects operating mode.
a) RMT - In this position, the PLAIN/ CIPHER selection is controlled by input outside the KY-75 control panel.
b) LOCAL - In this position, transmit mode is controlled by PLAIN/ CIPHER switch.
c) SIG CLR - In this position, if a fill device is connected to the FILL connector, the alarms will be set, and the selected fill register will be cleared. Upon release of the switch (it is spring loaded to the LOCAL position) the TSEC/ KY-75 will request a fill variable from the fill device. If fill device is not connected, a steady tone signal will be transmitted to all other units within the net, indicating a desire to establish communications on that link.
2) PLAIN/CIPHER switch - Selects plain or cipher mode.
a) PLAIN - The TSEC/KY-75 system will receive cipher and plain signals and will transmit plain.
b) CIPHER - Permits ciphered communication. (
3) P WR/FILL switch - Controls set power and fill positions.
a) OFF/ZEROIZE. All power is removed from the TSEC/KY-75 system and all fill registers are zeroized. (To enter this position, the switch must be pulled out and rotated counterclockwise.)
b) 1,2,3 fill positions. These positions are used to select the fill register of the TSEC/ KY-75 system to be used during transmission and reception of ciphered messages.
4) ALARM indicator. This indicator illuminates when a fill error, randomizer, or battery failure occurs. The indicator includes a press-to-test feature.
5) PLAIN indicator. This indicator illuminates when the PLAIN/CIPHER switch is set to the PLAIN position. The indicator includes a press-to-test feature.
6) CIPHER indicator. This indicator illuminates when the PLAIN/CIPHER switch is set to the CIPHER position. The indicator includes a press-to-test feature.
7) SIG/CIPHER RCV indicator. This indicator (blue) blinks continuously when the TSEC/KY-75 system is receiving ciphered text. The indicator includes a press-to-test feature.
8) PWR indicator - This indicator (white) illuminates when power isapplied to theTSEC/KY-75 system and the PWR/FILL switch is set to one of the numbered fill positions.
(9) FILL connector. This connector, located on the front of the TSEC/KY-75 control panel allows connection to a fill device.
(10) Processor connector. This connector, located on the back of theTSEC/KY-75 control unit, allows connection of the control unit to the processor via a cable.
When aircraft power is not applied to the TSEC/KY-75 and the standby fill batteries have been removed or are too weak to maintain the memory circuits, all storage registers of the TSEC/KY-75 will be zeroized within approximately 45 seconds.
A) TSEC/KY-75 System Turn-on Procedure:
1. PWR/FILL switch is set to any fill register number. Check that PWR indicator light is illuminated. 2. PLAIN/CIPHER switch to CIPHER. Check that CIPHER indicator light is illuminated.
3. PWR/FILL switch is set to each fill register (1 thru 3). If the position has not already been filled a steady alarm tone will be heard.
B) Filling TSEC/KY-75 Using General Purpose Tape Reader (KOI-18/TSEC):
1. FILL connector Connect to tape reader using fill cable (ON5124204).
2. PWR/FILL switch Set to register to be filled.
3. Insert the tape leader into the IN slot on tape reader. Line up tape feed holes with the white dots on tape reader.
4. RMT-LOCAL-SIG CLR switch Set to SIG CLR clear then release.
5. Pull tape through tape reader at a moderate rate. The steady alarm tone heard over the headset should stop, indicating a successful fill.
6. Repeat procedure for each register to be filled.
C) Filling TSEC/KY-75 System Using Transfer Device KYK-13/TSEC:
1. Verify that the transfer device contains the variables in its registers that are indicated on its writing surface by:
a. Transfer device mode switch OFF/CK.
b. PWR/FILL switch Set to register to be verified.
c. Transfer device initiate button Press and release. Transfer device indicator light will flash if the register contains a variable.
d. Repeat procedure for each transfer device register to be verified. NOTE Insure that the rubber grommet is in the KYK-13/TSEC P1 connector and that the TSEC/KY-75 PLAIN/CIPHER switch is in the CIPHER position.
2. FILL connector Connect to transfer device (either directly or with a fill cable).
3. Transfer device FILL switch Set to register containing variable to be transferred.
4. Transfer device MODE switch ON.
5. RMT/LOCAL/SIG CLR switch . Set to SIG CLR and release. Parity indicator light on transfer device should flash, and the steady alarm tone in the headset should cease, indicating a successful transfer of the variable.
6. Repeat procedure for each TSEC/ KY- 75 register to be filled.
7. Transfer device mode switch Set to OFF/CK and disconnect from TSEC/KY-75
D) TSEC/KY-75 Secure Voice Operating Procedure:
1. PLAIN/CIPHER switch to CIPHER. Check that CIPHER indicator light illuminates.
2. RMT/LOCAL/SIG CLR switch to RMT.
3. PWR/FILL switch - Set to desired fill register.
4. Microphone switch - Press. Wait for the preamble to stop, then talk into the microphone.
5. Microphone switch - Release. Wait for the postamble to stop.
The SIG/CIPHER RCVindicator light will flash during receipt of secure voice communications. After receiving a secure communications, wait until the postamble stops before initiating any transmission.
E) TSEC/KY-75 Clear Voice Operating Procedure:
1. PLAIN/CIPHER switch to PLAIN. Check that PLAIN indicator light illuminates.
2. RMT/LOCAL/SIG CLR switch to RMT.
3. Microphone switch - Press to talk, release when finished.
F) Zeroizing the TSEC/KY-75:
1. PWR/FILL switch OFF to ZEROIZE.
2. The steady alarm tone should be heard if the PWR/FILL switch is set to any fill position
All three fill registers of the TSEC/KY75 will be zeroized simultaneously. When aircraft power is not applied to the TSEC/KY-75 and the standby fill batteries have been removed or are too weak to maintain the memory circuits, all storage registers of the TSEC/KY-75 will be zeroized within approximately 45 seconds.
Reference: Technical manual TM 55-1510-220-10
|Front and rear views of the KY-75 RCU.|
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