Richard, I was having the same problem as you, since I own a first generation ThumbDV which runs at 230400 bauds. When I removed the –n argument in the command: python AMBEtest3.py -n -s /dev/ttyUSB0, it then worked for me. So for people with first generation ThumbDV’s, the command python AMBEtest3.py -s /dev/ttyUSB0 must be used. Also, on page 3, Steve says at point 8: DO NOT edit DMRGateway.ini UNLESS your DV is not at /dev/ttyUSB0 If you run a first gen ThumbDV, the baud rate must be changed in it also to 230400. And for Steve: thank you very much for all the efforts in the software and the documents. I went thru it all, and except for the items mentionned up here, everything went well and I’m ready for the next steps. Thanks and 73s from Guy VE2VAG