This is a switching unit which will select any operating combination of six transceivers, six transmitters, twelve receivers, six mike inputs, six speakers, and two linear amplifiers.

It was designed to accomplish the following:

1.  Selection of any receiver to operate with any transmitter, permit transceive or completely separate operation of a Collins S-line, and lock out all other units when any transceiver is selected.

2.  Connection of the push-to-talk, mike, key, audio output, and receiver muting lines to/from the selected unit(s) and provide logically sequenced T-R switching.

3.  Antenna connection and  changeover using external BNC relay boxes.

It has 2 sets of 6 ganged pushbutton switches, 9 illuminated pushbutton switches, 45 4PDT relays, 11 BNC relays, and 122 I/O jacks.  I've lost track of  the time expended for design (and redesign), construction, assembly, and test (as well as the parts cost), but it sure has been fun!