Well you should try "fldigi"- this is a tool with many modulation and demodulation schemes used for amateur radio- they end up going to the transceiver via audi

Well you should try "fldigi"- this is a tool with many modulation and demodulation schemes used for amateur radio- they end up going to the transceiver via audio so it works just fine between PCs using PC speaker and microphone. You can have many simultaneous users on different channels within the audio bandwidth. https://sourceforge.net/projects/fldigi/files/fldigi/ https://sourceforge.net/projects/fldigi/files/fldigi/ One of the more entertaining modes is Hellschreiber: basically a radio fax: https://en.wikipedia.org/wiki/Hellschreiber https://en.wikipedia.org/wiki/Hellschreiber