[1000mp] MP Startup Issue

[ARS NZ3O (Byron) FM29fx]

My station consists of the control PC with the
following conntactions:

1. Serial CAT to MP
2. LPT keying to MP
3. Serial control to Rotor
4. Serial PTT to RIGblaster (not used)

The other day, and once some months ago,
when I powered things up, my MP came up
in transmit mode, in spite of the fact that neither
VOX or MOX were pressed.  (Sounds like RIG-
blaster PTT so far).

So, I power-cycled the MP.  When it came back up
it woudln't transmit until I pressed MOX.  Then I used
my PC keyboard to send CW under MOX and things
returned to normal.

So, if PTT from RIGblaster is active, did the MOX/send
reset something for me, or was it not RIGblaster PTT 
and possibly something with the radio?

73, Byron