Data over normal GSM call

Joe Pfeiffer joseph at
Tue Apr 8 19:12:38 CEST 2008

Diego Fdez. Durán writes:
>On Tue, April 8, 2008 18:02, Joe Pfeiffer wrote:
>> Andy Green writes:
>>>Hash: SHA1
>>>Somebody in the thread at some point said:
>>>| On ti, 2008-04-08 at 16:02 +0100, Andy Green wrote:
>>>|> I think you're right, but just a thought if you could issue
>>> ready-coded
>>>|> GSM codec frames, you can put the data direct in there for
>>> >1KBytes/sec
>>>| Yeah, but you can't.
>>>"can't" is pretty strong... isn't "not without seriously hacking
>>>something around" better?
>> If I understand the limitation correctly, in this case, I think
>> "hacking something around" involves hacking at least firmware and
>> quite possibly hardware inside the gsm modem.  That's close enough to
>> "can't" that the difference really doesn't matter.
>Can't you initiate a voice call between to FreeRunners and then use the
>mic and mixer devs to modulate the data as sound?

Yes -- but that's the technique with the claimed limitation of roughly
1Kbps.  It isn't inserting the raw gsm codec frames.

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