I have been using the serial library with some partial success, and am looking how I may avoid data loss. This is with no lower-level handshaking, just a package protocol (actually from Garmin for their GPS). The Help for the serial keywords doesn't say much about how they interact. For instance I assume that doing InputArray() empties the input buffer so that the same data cannot be read again. But what is the effect of the Timeout? What actions does it influence, and how to tell if there has been a timeout event? Regards, Mike.