Stopping Procedures

TM 11-5895-555-24

( 4 ) Press the appropriate push-to-talk

(4) Set the intercom system of the aircraft

or radio console to accept. AN/ARC-54 (fm

switch on the aircraft or radio console and then

immediately release. The tone in the headset

radio) communications. Refer to appropriate

should disappear. The Cipher equipment is now

equipment or aircraft configuration manual for

in the standby condition.

details. Caution: The POWER ON switch must

be in the ON position, regardless of the mode

NOTE

of operation, whenever the C-8157/ARC is in-

If the tone does not disappear from the

stalled in the aircraft.

headset, a malfunction of the appropri-

(5) Insure that Cipher/Plain locking plate

ate Cipher equipment is indicated.

is in the desired position.

Higher level maintenance is required.

b. Plain Mode Operation.

(5) To transmit, press the press-to-talk

(1) Set the PLAIN-CIPHER switch SW-1

switch. DO NOT TALK! In approximately 1/2

to the PLAIN up position (fig. ll, 1-2). This

second, a beep will be heard. This indicates the

may be secured in the Plain position by installa-

receiving station is now capable of receiving your

tion of the locking plate to prevent accidental

message. Transmission can commence.

depression to the CIPHER position by the opera-

tor. PLAIN indicator lamp L2 (red) should il-

NOTE

luminate.

Only one TSEC/KY-28 can transmit at

( 2 ) Set RE-X/REG switch SW-2 to the

a given time on a given frequency. Si-

REG (down) position.

multaneous transmission by two (or

( 3 ) Press the appropriate press-to-talk

more) TSEC/KY-28 equipments on the

switch located in the aircraft or radio console.

same frequency will result in the garb-

(4) Speak into the microphone to transmit.

ling of messages and possible loss of

Release the press-to-talk switch to receive.

synchronization in the receivers. Al-

NOTE

ways listen before attempting to trans-

If during reception a short beep is heard

mit to assure another transmitter is not

on.

in the headset, it is an indication that

a Ciphered message is being received.

(6) When transmission is complete, release

When such a tone is heard, the control

the press-to-talk switch. The Cipher equipment

indicator and the TSEC/KY-28 Cipher

is now returned to the standby condition.

equipment must be adjusted for receipt

(7) To receive, it is necessary for another

of a Ciphered message. (Cipher opera-

station to send a signal first. Upon receipt of

tion may also be secured in the like

the signal, the Cipher equipment will be switched

manner as PLAIN by positioning the

automatically to the receive condition. At the

locking plate against accidental depres-

sion into the PLAIN mode of operation),

same time a short "beep" will be heard in the

headset. Reception will then be possible. Upon

c. Cipher Mode Operation.

loss of the signal, the Cipher equipment will be

NOTE

automatically returned to the standby condition.

If the control indicator is utilized for

Ciphered communications, refer only to

(8) If retransmission facilities are required,

s t e p s (1) through (7) below. If re-

set RE-X/REG switch SW-2 to the RE-X (up)

transmission facilities are required, re-

position.

fer to steps (1) through (8) below.

(1) Set PLAIN-CIPHER switch SW-1 to

3-3. Stopping Procedures

the CIPHER (down) position. CIPHER indica-

a. Normal.

tor lamp L3 (green) should illuminate.

(1) Set POWER ON switch CB-1 (fig, 1-1,

(2) Set RE-X/REG switch SW-2 to the

REG (down) position.

1-2) to the off (down) position.

(3) A constant tone of 1,200 CPS should be

(2) Perform the stopping procedure for

heard in the headset. This tone should be heard

Radio Set AN/ARC-54 (or equivalent) in ac-

for approximately 2 seconds. At the end of that

cordance with the appropriate equipment and

interval, the tone should commence to be inter-

rupted at a rate of 2.3 CPS.

Aircraft Configuration manual.

3-2