Cases were aluminum box extrusions discovered at
a local surplus dealer (unfortunately sold out!) Belt
clips are "key ring clips" from local hardware
store (cut in half).
Left to right: Volume control; combination mic mute
and "call" switch, red signal light, 1/8" mini jacks
for cheap computer headsets, and industry-standard
4-pin male XLR connector for standard headsets.
XLR female and male 3-pin connectors for loop-through
(daisy-chain) interconnection of intercom units with
standard mic cable. On the right is an external signal
light output jack (for TV camera use).
