Thanks for trying it out! It would be great to get that working, but the GSM voice compression of a mobile phone is tough beast to beat. Also, some 'retro' handsets say they 'enhance' the sound, thus I believe there might some filters in those.
One standard data protocol that is able to go through GSM voice compression is the dual tone frequency matching (DTFM). This can be used for data, but it would be slower, and of course would require its own terminal program with DTFM coder/decoder on both ends to be useful. DTFM encoders/decoders are commercially available... Peter Vollan <[email protected]> kirjoitti 19.12.2015 kello 0.56: > Yes, eliminate the Acoustic Coupler from the equation. > > On 16 December 2015 at 11:03, Mark Wickens <[email protected]> wrote: >> Thanks for the responses - as it happens it was more down to me not entering >> the modem stat specification correctly into the terminal program. Once I got >> something accepted then I heard the 'ping' of the relay to switch in the >> modem circuit and was able to hear the familiar screeching via the acoustic >> coupler. >> >> I haven't got anything to work reliably however which is a shame but it was >> a long stretch. I bought a 'retro' bluetooth handset and paired it with my >> mobile phone. There may be still some mileage in it but I suspect there are >> too many compression algorithms in the way. >> >> I may need to resort to a direct connection cable or external modem instead. >> >> Mark. >> >> On 16 December 2015 at 18:30, John Gardner <[email protected]> wrote: >>> >>> Historically, telecom regulation in the UK was rather different >>> >>> than what we're used to - Television receivers required licenses, >>> >>> for instance. Data was charged for by the byte. I'm speculating >>> >>> that built-in modems may have (had) some similar dis-incentive >>> >>> built-in for the manufacturer or retailer. >> >>
