Section V. CONTROL AND FREQUENCY SELECTION CIRCUITS

Figure 25. Radio Set AN/TRC-68, power control, schematic diagram.

Section V. CONTROL AND FREQUENCY SELECTION CIRCUITS

b. Energizing Tr Relays.

82. Push-to-Talk Circuit

(fig. 26)

(1) Tr relay K601 is energized by

26.4 volts from Dynamotor DY-

a. General. The rt unit functions as a

151/U (AN/VRC-24) or PP-1494

receiver in standby operation. When the

(AN/TRC-68) when NOR-BB switch

push-to-talk switch of Microphone M-29A/

S801 is in the NOR position. The

U (RT-323/VRC-24) or Handset H-33/PT

push-to-talk switch completes the

(RT-441/TRC-68) is pressed, or when a

ground circuit to relay K6-1 and

a retransmit ground is supplied from the

the relay operates.

AN/GRC-3 through -8 equipment, the rt

unit functions as a transmitter. The push-

(2) Tr relay K601 can be operated from

to-talk circuit receives 26.4 volts dc from

Radio Set Control C-1439/U only

the broadband encoder supply when NOR-

when radio-interphone s w i t c h

BB switch S801 is on the BB position.

S1504 is on the RAD or RAD-INT