[Milsurplus] Help needed with HLI device

[Receiver]

A blue box followed me home from the Lawerenceville, GA hamfest in November. 
It was aon a table full of portable and not so portable test equipment.  The 
thing is called HLI Remote Signal Extender, Model 67R-M, serial no 502.  It 
looks like early sand state with IC voltage regulators.  Has jacks, 
switches, binding posts and a few controls.  It has a property tag from the 
Illinois State Police.

I'm sure that HLI stands for Hekemian Laboratories, Inc.  In MD.  They were 
a manufacturer of advanced telecommunication test equipment and systems.  I 
see by Google that they were purchased in 2001 by Spirent Communications. 
Investigating their website revealed nothing about Hekemian products.  I 
also noticed that some of the Hekemian products were sold to Harris/Dracon 
division.  No luck there so far.

I am seeking a manual or at least schematics of this box.  It looks too nice 
to raid for parts while there us a chance it could be adapted to some other 
use.

Does anyone recognize this gadget? Can anyone help me find out anything 
about this box?

TIA,
John, W4NET