ICOM CIRCUIT SPECIAL INTERCOM.

TM 32-5895-227-14&P

a. Telephone wiring at J2 is directly coupled, pin-

b. The circuit is completed at J5 of SB-2600/G

to-pin, to J2 of SB-2602/G Intercom position. The relay

outstation position. The answer function is completed at

and switching functions at J2 establish the third channel

SB2600/G by flipping INTERCOM-CCC switch up and

of the ICOM.

energizing relay K8. The blinker circuit is deactivated

b. Under the referenced circuit, communication is

and a steady-state green light indication is obtained.

This condition indicates an active channel. ICOM

completed between the SB-2602/G operator, the DFR

communication with a headset and a mike through audio

operator, and an outstation position SB-2600/G or a TA-

volume compression unit AMP 1 and AMP 2 at OA-

676/G.

7735/G is established with the SB-2600/G headset and

mike through AMP 3 and AMP 4.

6-11 AUDIO VOLUME COMPRESSION CIRCUIT .

c. Typical installation of six circuits is found in an

outstation MMBV-2A Van. Details for this installation

a. Volume levels of all signal and intercom lines

can be identified in Installation Bulletin Number 81,

are maintained at a constant 4DBM (zero decibels,

MMBV2A HF Radio Receiving Central.

maximum) level by use of a standard compression

circuit as shown in figure 6-8. The basic circuit consists

6-10 ICOM CIRCUIT SPECIAL INTERCOM.

See

of a 4-transistor stage compandor, with output voltage

figure 6-7. Multiple position ICOM communication can

level limited at emitter of Q4.

be established as illustrated in figure 6-7. Outstation

Volume

compression

circuits

are

communication is identical to the detailed explanation in

transistorized, printed circuit board plug-in assemblies.

paragraph 6-7. A special telephone TA-676/G position

These circuits appear as AMP boards in OA-7735/G,

Direction Finder Report (DFR), coupled with a Sit

SB-2602/G, TA676/G, and SB-2600/G.

Control Operator and an outstation, can establish three-

way intercommunication.

6-9