Donald J. Bartley wrote:

> The module has the ability to do up to 19200 bps but they can't
> guarantee that speed because of the inaccuracy of the ceramic
> resonator they use for timing.  The fastest they could guarantee was
> 9600 bps.

  I keep reading comments like this.  Think about it.  It's rubbish!

  It doesn't matter *what* baudrate you use, a given percentage error in
timing will have the same effect on synchronization.

  The only three problems you can have with higher baudrate are:

 1} Impedance and termination mis-match in a given transmission line
becomes more significant the higher the frequency.

 2} The processor must be fast enough to service the UART or "bit-bang"
routine at the right times.

 3} For a given non-integral multiple of the baudrate used as the
ceramic resonator *or* crystal frequency, the error in the approximation
naturally increases for the higher baudrates.  I presume this is what is
meant by the comment above.
--
  Cheers,
        Paul B.