[Heath] SB-110A?

[George Babits]

My "new" SB-110A arrived  a couple of days ago and I'm starting to see if it 
works.  One thing has me mystified and that is a 9 pin "molex" type plug in 
the middle of the rear.  There is a square hole in the back of the cabinet 
that allows access.  The sides of the hole are match the back of the cabiner 
paint and color wise.  The wiring (4 leads) to the plug appear to be bundled 
into the wiring harness.  I see nothing in the manual relating to this, yet 
it looks "original."    In the xerox partial copy of the manual was a 
schematic of the SB-102 which does show this connector aand it looks like it 
may be for breaking the PA screen lead.

Is this original or a modification?  Anybody got any ideas?

Thanks and 73,
George
W7HDL