Section II. RETRANSMISSION CIRCUIT FUNCTIONING

TM 11-5820-498-35

c. Muted Audio Signals to Crewmember Con-

the crewmembers can be heard over the radio

trol Boxes. When a crewmember control box

audio signals, since both sources of audio signals

MONITOR switch is set to ALL position, muted

are avaiIable when the crewmember control box

audio signals (reduced strength by passage

MONITOR switch is set to ALL position. Muted

through R15 in AM-2060(*)/GRC) can be heard

audio signals received at the receiver-transmitter

at the audio accessory at each crewmember con-

are distributed to the crewmember control boxes

trol box. The receiver-transmitter audio signal is

as follows:

reduced so that the intercom audio signals among

From

Unit

Receiver-transmitter . . . . . . . . . . . . . . . . . .

Module A25/A55 . . . . . . . . . . . . . . .

J9, pin B

Pin B . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CX-4655/GRO . . . . . . . . . . . . . . . . . . .

Pin B

AM-2060(*)/GRO . . . . . . . . . . . . . . . . . .

J2, pin B . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Audio amplifier Q1, Q2

Audio amplifier Q2 . . . . . . . . . . . . .

R15 (muting resistor)

R15 . . . . . . . . . . . . . . . . . . . . . . . . . . .

J9, pin K

Pin K . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pin K

CX-4723/VRC . . . . . . . . . . . . . . . . . . . .

S608 (OFF position)

AM-1780/VRC . . . . . . . . . . . . . . .. . . . . . . .

J501, pin K . . . . . . . . . . . . . . . . . . . . . . . . .

K502, terminals 18 and 19

S503 . . . . . . . . . . . . . . . . . . . . . . . . . .

Interphone amplifier A520

K502, terminal 19 . . . . . . . . . . . . . . . . .

Interphone amplifier A520a . . . . . . . . .

J504, pin L

Pin L

Pin L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CX-4723/VRC

...............

S801 (ALL position)

J801, pin L . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C-2298/VRC . . . . . . . . . . . . . . . . . . . .

R801 (VOLUME control)

S801 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

R801 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

J802 and J809, pins B and E to

audio accessory earphone

J506 (J506, J507), pin L

AM-1780/VRC . . . . . . . . . . . . . . . . . . . . . . . . Interphone amplifier A520 . . . . . . . .

Pin L

CX-4723/VRC . . . . . . . . .. . . . . . . . . Pin L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

S902 (ALL position)

C-2298/VRC . . . . . . . . . . . . . . . . . . . . . . J904, pin L . . . . . . . . . . . . . . . . . . . . . . . . . . . .

S902

R902 (VOLUME control)

. . . . . . . . . . . . .. . . . . . . . .

R 9 0 2 . . . . . . .. . . . . . . . . . . . . . . . . .

J902 and J903, pins B and E, to

audio accessory earphone

S902b . . . . . . . . . . . . . . . . . . . . . . . . . . . .

S901 (EXT position)

S901 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

J901, pin J

Pin J . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pin J

Cable (fig. 4-6, note 7) . . . . . . . . . . . . . . . . .

J61, pin J . . . . . . . . . . . . . . . . . . . . . . . . . .

R61 (VOLUME control).

C-2296/VRC . . . . . . . . . . . . . . . . . . . . . . . . . . .

TB61, pin 5

R61 . . . . . . . . . . . . . . . . . . . . . . . . . . . .

H-207/VRC earphone

TB61, pin 6 . . . . . . . . . . . . . . . . . . . . . . . . .

Indicates parallel connections from interphone amplifier A520.

Indicates paralled connections from S902.

Section II. RETRANSMISSION CIRCUIT FUNCTIONING

used to provide the connection between the re-

2-6. Radio Retransmission Circuits, General

c e i v e r - t r a n s m i t t e r s at the relay site. The

(fig. 4-7 and 4-8)

MK-456/GRC consists of a canvas bag and a 50-

a. The receiver-transmitter in the AN/VRC-53,

foot Cable Assembly, Special Purpose, Electrical

A N / V R C - 6 4 , AN/GRC-125, and AN/GRC-160

CX-4656/GRC. Two circuit boxes, a choke box,

can be connected with another receiver-transmit-

and filter box (fig. 4-7) are included in the cable

ter for the purpose of setting up a radio relay site

assembly. An audio accessory can be connected to

for automatic retransmission of radio signals

the receptacle on the choke box to monitor audio

from radio stations that are too far distant from

signals applied through the retransmission cir-

each other for direct radio communication. The

cuits. When the two radios at the relay site are

other receiver-transmitter at the relay site can be

set up for providing retransmission to the two

t h e RT-505/PRC-25 or RT-84/PRC-77 (para

distant radio stations, the keying of one relay site

2-7), or it can be the RT-246(*)/VRC or

receiver-transmitter to send the signals to one

RT-542(*)/VRRC

(para

2-6)

from

the

distant radio station is automatically arranged by

AN/VRC-12 radio series. (RT-246(*)/VRC and

the other relay site receiver-transmitter that i

RT-524(*)/VRC represent all models of each re-

receiving the signal from the other distant radio

ceiver-transmitter.)

station.

b. Retransmission Cable Kit MK-456/GRC is

2-8