John - your post is very helpful. The first thing I checked is do we really need to output in binary mode, and the answer is unfortunately - yes. Turns out that forward modelling suggests a resonant frequency somewhere between 100 and 300 Hz. So, to avoid aliasing, we need to sample at double the highest frequency of interest. That means our Nyquist frequency is 600 Hz minimum. The gizmo says it samples at 595 Hz at the highest baud rate and in "binary output mode". So, I'm stuck having to do it the hard way (if I can).