Thanks to all who helped with my rs-232 and IRQ problems.  It's working,
and all is resolved!
'nuther subject.
Has anyone done anything with a PIC as a bandpass filter?
I was thinking that perhaps if a "gate" was open for a fixed and certain
time, and a number of incoming pulses were counted before the "gate"
closed, anything other than the correct count would be off frequency.
Trouble is, how does one open and close the "gate"?