well... first observations,
i don't see any DISABLE and ENABLE 'round the ISR.

RESUME should not be followed by a label name,

and you don't reset the INT bit.

So yes it may cause some weirdnessssssssss.

And the following will explain when using pull-up/down for serin and timeout
http://www.picbasic.co.uk/forum/show...86&postcount=5