RECEIVER
1
---1
EXPANDER
I--"~
..
--------
AUX
OUT
RECEIVER
2
---1
EXPANDER
I
BALANCE
INTERCOM
GAIN
~
TRANSMIT
OUT
HEADSET
INTERCOM
---------
...
~
SPEAKER
RS
HIGH/LOW
~_------toI
AUX
IN
DYNAMIC/
ELECTRET
AUX
GAIN
~
RECENER
3
---1
EXPANDER
I
RECEIVER
4
---1
EXPANDER
I--"'~--"'/
HEADSET
MICROPHONE
Figure 20
Block Diagram Versions 3thru 6
3-32