[hardware v1] GSM audio question

Robert Michel openmoko at robertmichel.de
Wed Dec 6 16:08:19 CET 2006

Salve Sean, *!

Beside serial at-command communication with the GSM chip, 
could I can get also the audio (encoded with the GSM-codec)
undecoded from the GSM chip (as digital 9.6 or 14 KBit/s stream)? 

==answering machine==
Imagine an answer machine solution
- it would be smart to fetch the original GSM audio data without
decoding to analog audio... that would encrease the quality and
would cost less CPU/battery power.

E.g. when I use the CPU hard (routing, playing, office applications...)
then the answering machine could get the call without using much CPU

And to play back the answering machine, it would be smart, when
the GSM chip could do this - decoding the GSM encoded recording

==call monitoring==
when I like to record all my calls (with two channels) I would
like to fetch the GSM encoded 14kBit/s audio stream from the GSM chip,
instead of record it analog and do the compression with the CPU

==DSP in general(nice but not so important)==
I could imagine that a GSM chip could do audio processing with
less power consumtion then the CPU - when the DSP could get be
loaded with high quality MP3/Ogg/Vorbis codecs - maybe:
- less power consumpting for audio playback
- less CPU power needed - more resources for video decoding

Of course I will not do encryption by encrypt GSM encrypted
audio stream - my thougths are just how "answering machine"
and "call monitoring" could be done more efficient - so this
is why I ask if the GSM chip does support it, or if it would
be possible that FIC asked (pay) the GSM chip producer for
an advancement.
Will be the GSM-chip flashable? So that such a feature could
become v1.1?


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