Re: GSM and GPRS

On Tuesday, 26 April 2005 at 21:18:16 (+0200), Holger Freyther wrote:
> On Friday 22 April 2005 20:51, [email protected] wrote:
> > Personally I don't intend to stop using my simpad soon. Now now I hav=
e
> > bluetooth working, and sandisk 128Mb+wifi almost working, and a wavec=
om
> > GSM module that's waiting on my desk :-) Moreover, having a working d=
ual
> > boot with wince would be an interesting challenge, or adding more mem=
ory,
> > or tweaking the bootloader, etc.
> Hi,
> where do I get GSM modules from? Can one get a datasheet as well?

The cheapest I've found is 74 euro :
http://www.budgetcom.nl/product_info.php/products_id/34

I recommand you purchase one, because it usually costs far much. The
firmware can also be updated and I've got the full specs and AT
references.  (google for DeveloperGuide-ModemModule-GSM-GPRS-RevE.pdf
WMOi3%CB%B5%C3%F7%CA%E9.pdf or "MAN-P2B0007-0008 COMPACT_ita_ed1.pdf")

It's sold with an antenna connector - pierce your simpad to hook this
connector, so you can plug in an external antenna if you want.

Ordered 2 to get a reducted rate and to try to solder it to another
device too :-) (maybe to my zaurus 6000 sled?) Now I need to figure
out if the simpad external serial port gives TTL (3.3V) or RS 232 (5.0
V). opensimpad says 12V but I don't think so - will do some measurements.

I also need to get 5v 1.2A to power the gsm module (it normally needs
much less, but the specs says you should be able to give that for peak
demand)

I also have to try to find where I can hook it up, at the moment I
have no idea. Since I rarely use IrDA, never the smartcard, and very
little the external port (only for flash/bootloader), these are my
candidates. The external serial port is the best candidate since
there's also audio ports and I would like GSM voice functions as well
as GPRS, so it may go there with a switch to toggle between functions.

To try that, today I took my old S25 cable (I'm a big fan of siemens
hardware :-) and soldered it to do some voltage and amperage measures
on the external serial port.

So you see it is a hack in its very early stages.

Hopefully I will be able to use the simpad speaker and microphone for
the GSM module. In the worst case, the audio will be diverted to the
bluetooth chip after being encoded by an ADC, so that I can use a
bluetooth headset with my "gsm simpad".

Ideally I would be able to use both (default to internal when no
bluetooth headset is available), but I'm not sure how to do that
without using an hardware switch. Tille, any suggestion?

Guylhem

--=20
Bien =E0 vous - Best regards,
Guylhem P. Aznar

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ey


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