I checked with a HP and power unit and they are indeed little different positioned than on a 19 set.
The odd one fits easily so it came with the lot of ws kit including a HP. I know now why it didn't fit a 19set + PU set up. Was just considering to make it fit.
see pictures; first one is inside with the extra wires connected in the centre and the second one with the ordinary bone.
top one in the second picture is the HP one
the odd thing is they have the same ordering number????
Connector
12 pt No 23A
(Canadian)
RCA 110076
Now the bad new I cannot sell it sorry
Peter Hommes
http://www.milmarket.org