Hi Ed,
A link to the datasheet for the sensor in question, or at least a part number would be a good idea to post. Somehow Norm knew or assumed its output was RS232, something you didn't say in your first post, so my question is: Is it?

If the sensor is indeed outputting async serial it may be doing so at TTL levels and your PC may not like that (even though it usually works for short distances) so you may need a MAX232 driver or something.

A diagram showing how you have it connected would be nice as well.

But again, without even knowing what type of sensor you're talking about it's just guesses.

/Henrik.