http://knut.one/wav2cas.htm
Here is a nice write up of it in use with a Model 200: http://munk.org/typecast/2014/07/25/file-transfer-for-trs-80-model-100102200-using-a-digital-audio-recorder-the-road-less-travelled/ and video: https://www.youtube.com/watch?v=exdiQdjioyQ Darren Clark