[Milsurplus] BC-348 variant?

[jcoward5452 at aol.com]

Hi Folks,
 Saw this one on the auction block and maybe someone could illuminate:


  260368098224


What was this version for and what is the connector on the front panel 
for?

 Thanks,
            Jay KE6PPF

PS Looks like a  "Q" or similar to begin with.