In a message dated 15/12/97  20:52:46, you write:

<<
 The open-collector output pins (e.g. RA4 on 16C84) are not clamped to VDD,
 and can safely take a voltage above VDD; one of the Microchip guys quoted
 14 volts.  >>
As this pin doubles as the Vpp does this not force the pic into program mode
at 13v and stop program opperation if so it would be unwise to use this pin in
this mode of opperation unless you want to write self modifing code ???

That would provide some interesting results if possable !
Just my .02 worth
Cheers Steve,,,,,