ISM868 bands that are located adjacent to the GSM 850/900 frequency allocations. My initial investigations and enquiries indicate that this should be possible by creative programming of the baseband processor in many models of phones. The trick, as I suspect you well know, is the difficulty in getting the information and tools required to reprogram these radios. I am now in a position to potentially fund further work on this. So, as the open-source group with the most experience reprogramming baseband radios, what is the feasibility of creating a proof-of-concept using the types of phones you already work with to send and receive arbitrary data packets without reliance on a cell tower (even for time synchronisation)? I know there are a lot of constraints and problems, but I am most interested in creative solutions that can get us to a working prototype, however crude, that can be used to demonstrate the feasibility of what I am proposing. If this discussion is off-topic here, I am happy to hold the conversation at the serval-project-developers google group, but I am equally comfortable with it continuing here. Thanks in advance, Paul Gardner-Stephen. Shuttleworth Telecommunications Fellow at Flinders University.