Quote Originally Posted by bcd
Is it possible the inline box it could be some kind of volume limiter circuit for the headset? I know in European broadcast stations that all the headphones have to be fitted with dB limiters to stop the operators from damaging their hearing.
http://www.canford.co.uk/commerce/it...1_2001812.aspx for example.

Most of them use back to back diodes, but if it is military gear they have the money to do things the expensive way...

Bill.

Interesting thought. The 2 transistors on the board, while they aren't diodes, can sure be set up to act like it.
JDG