(a) Z 1-5. Used to zeroize positions 1 through 5. Switch must be pulled out to be set to
this position. Positions will be zeroized (erased) automatically when the switch is placed in this
(b) 1-6. COMSEC key positions. Used to store and utilize keys.
(c) Z ALL. This position is used to zeroize all six fill positions. The switch must be
pulled out to be set to this position. All fill positions are zeroized when the switch is set to this position.
(5) Mode switch. The mode switch is used to select the function you want the KY-57 to
(a) P - plain. Selects the plain function. When in this position, the KY-57 is not
scrambling the transmission. Switch must be pulled out to go to "P" so it can not be set to this position
(b) C - cipher. Selects the secure mode. Transmissions are being scrambled when the
KY-57 is in cipher.
(c) LD - load. Used to load keys from the fill device into the KY-57.
(d) RV - receive variable (key). Used to receive remote keying.
(6) Volume. Adjusts the receive volume only.
(7) Power switch. Applies operate voltage to the KY-57.
(a) OFF/ON. Turns power ON and OFF.
(b) TD - time delay. Used when the KY-57 is being used with a retransmission station.
(8) Battery connector. Electrical connection from the battery to the KY-57 in the backpack
(9) Battery. BA-5590 is a lithium battery used to supply operating voltage to the KY-57 in
the backpack configuration. Life expectancy for the battery is approximately 40 hours of balanced
transmit and receive operation.
(10) Battery box. Attaches the battery to the KY-57 and protects it from damage.
(11) RT interconnect cable. Connects KY-57 to radio.