[Milsurplus] Antenna Coupler ID needed

[antqradio at juno.com]

Greetings
I bought this antenna coupler a few years ago still mounted in the
shipping crate with property tags (or what was left of them) attached.
Already has Mods 2 and 3 installed.

The following is from the equipment tag:
FSN 5821-658-3692
GHSC 5836-8M2
MPN XR73785-4
T.O. 12R2-4-7-507
Anyone know the pin out of the power and control cables, power, 
frequency range and what equipment is was designed to go with?

Regards from Hot Springs, AR
Jim