A while back I asked for some help regarding converting
a stream of data (made up from the following set of data)
into an audio signal that could be recorded on a cdrom.=20
When the audio was played back it needs to be converted=20
back into the original stream of data and fed out a serial=20
connection (to control some servos).

Sync/Command bit     Servo number            Position
255                           1-254                        1-254
=09
Several of you suggested looking into a modem on a chip type
IC to do the generation and decoding of the audio and them record
audio or process the resulting data. I looked into this quite a=20
bit but I cant seem to find a modem IC that doesn=92t require=20
training/synchronization to occur before sending or receiving data.=20

So I looked into DTMF tones to represent the data but I found
out that DTMF decoding requires a minimum 20ms tone and a minimum 40ms=20
pause between tones. This would only allow me to send a couple sets of=20
data per second. I am shooting for 30 sets of data per second.=20

Does anyone else have ideas on how to generate an audio signal that can=20
cleanly encode 90 bytes per second (3 bytes per set X 30 sets/ Sec). And =
then decode that audio signal back into the original data=20
stream from a recorded source (Some sort of simple IC that could be
interfaced with a PIC would be great:)=20

Thanks,=20
Mike



--=20
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