On 13/09/2007 00:10, Pete Turnbull <pete at dunnington.plus.com> wrote: I went one step further than that. I bought a couple of telephone line isolating transformers with a view to building some modems from magazine projects so that I could exchange programs with a friend who, like myself, had a BBC micro. I took a long time to get around to building the modems but in the meantime, I experimented with hooking the cassette port on the BBC to a phone line via a transformer and put in place a similar setup at my friends house. We used phones to make the initial connection and then switched in the transformers and issued LOAD and SAVE commands to transfer data. It was difficult to get everything synchronised correctly. Block numbers were displayed at the receiving end when data was being received but the sending end had no idea if things were working or not and the voice channel was not available while attempting transfers. As far as I recall though, we did manage to successfully transfer files at 300 baud but we didn't persue the idea further because of the slowness of the transfers and difficulty of setting everything up, not to mention the possibility of an error when transferring a large file requiring us to restart from the beginning. Regards, Peter.