In general to all of the good folks who responded to this query,=20 let me say thank you, I had been feeling around he edges of=20 the In-rate vs Out-rate but hadn't quite gotten there. Actually, the PIC UART clock and the MAX3100 clock are from the same crystal - I used an 18.432 MHz xtal for the PIC and=20 "borrowed" it via a /10 chip down to an 1.8432 clock into the=20 MAX3100 (which is just about its max clock rate). If you do the=20 division on 18.432 MHz the baud rates should come out dead=20 in the center of each rate's tolerance window. So I would have=20 to think that the clocks are in dead synch with each other Also, I find in testing that ONLY the 115.2 rate gets through=20 without dropping the byte - at least on the systems I have tested so far. The LOWER baud rates are the ones dropping bytes. This is true on 3 different PCBs with many different data sources & data sinks. But I am going to try the flow-control idea, since it just sounds=20 good. Unfortunately, most of the devices which plug into the=20 Output side have no flow control capability, but the modem supplying the data feed always does, so I will try pausing the=20 data flow every 100-200 characters, for a few character-periods,=20 to let the MAX3100 catch up. We will see how this goes. RJG -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist