Ok, here's the status after several different approaches: - the program runs nicely in the DOS-Box with qb11, i.e. interpreter-mode, and the USB-RS232 communication as "COM2" works - the same program compiled with qb64 results in a "bad file mode" error, and the interface isn't working - still the …

Hurray, great, thanks to Gmlb256! The interface is up and running now. Perfect - you saved my day & week :-) Next thing I'll try is to get my programs compiled by qb64 running as well - because I've seen in the wiki that soundfiles can be embedded there (we'll see how more or less easily that works …

Thanks, DosFreak, I've tried now, but at the output time (i.e. command "PRINT #2, a$;"), I'm getting the response "Unhandled Error #54: Bad file mode". I'll try now the suggestion of Gmlb256

I have a model railway which is controlled digitally - meaning that tracks and signals are switched end-to-end according to the time-table, trains start and stop as configured, etc. The model railway is Märklin with decoders from Trix (Selectrix). The program was developed by me in QBASIC on Windows …

Sorry, wrong thread - I've deleted my post here and moved them to DOSBox (DOS-Box general items)