I really don't see the point, given how ubiquitous data is, at least at EDGE speeds, and how expensive international long distance remains. I'd rather have som

I really don't see the point, given how ubiquitous data is, at least at EDGE speeds, and how expensive international long distance remains. I'd rather have something which degraded to half duplex voice messages (and IM) relaxing hard realtime on the slowest data links. I also want wideband audio whenever possible (which is frequent). There were open source systems which used CSD/HSCSD on Windows CE ("cryptophone", in early incarnations), and systems which did used analog phone lines and then modems and slip/ppp (I think a plugin for speak freely), but neither analog lines nor HSCSD are particularly common these days. Even the military stuff moved to ISDN, largely.