[Milsurplus] Indicator, digital display

[Glenn Little WB4UIV]

I am trying to identify a piece of equipment that I uncovered.
This is marked ID-1707A(V)1/U.
It has 6 nixie tunes to read out Hours, minutes, and seconds.
I has an input filter switch on the front with the following positions:
250 Hz, 1000 Hz, 20 KHz, 40 KHz and 80 KHz.
Also on the front is a switch marked 1000 Hz/250 Hz, a switch marked 
Reverse Code Control and a power switch.
The rear has a 0.75A slo blo fuse in holder, a 4 pin connector marked 
AUX OUTPUT, a 3 pin power input connector, a 24 pin parallel output 
connector, a BNC connector marked INPUT and a BNC connector marked OUTPUT.
Power comes in through a nice power line filter.
The logic is TTL with date codes indicating that this was built 
around mid to late 1974.
The logic board is wire wrapped indicating only a few were built.
The input circuit is on a PCB marked ASSY A3 ON175006.
Other pieces have ON numbers on them indicating that this was 
possibly crypto related.
This is built into a rack mounted cabinet that looks to be 2RU high.
It has a property tag indicating that it once was at N00069.

Does anyone recognize this?

Before I part it out, I would like to know what it was intended for.

Thanks
73
Glenn
WB4UIV