Data call (aka CSD) with QtExtended
openmoko at mazikeen.demon.co.uk
Wed May 6 00:31:10 CEST 2009
On Tuesday 05 May 2009, Franky Van Liedekerke wrote:
> On Tue, 5 May 2009 22:44:49 +0200
> Mile Davidovic <david.moko.comunity at gmail.com> wrote:
> > Hello
> > My understanding is next:
> > - qt extended have support for CSD but quite rudimentary (these words
> > are from qt extended documentation)
> > - sample qt application works fine with CSD but only first time (they
> > have problem with releasing resources)
> > In general, OpenMoko is capable of working with CSD but my
> > understanding is that CSD (at least on Qt) is not preferable working
> > scenario.
> > Regards
> > Mile
> Hi Mile,
> I'm sorry, but I'm not really familiar with CSD calls, could you
Circuit Switched Data, the original GSM data mode where the phone acts as a
slow (9600) conventional modem. Later HSCSD increased the speed a bit by
channel bonding. My k700i will let you select between analogue and ISDN modem
behaviour, handy when calling an ISDN line as it doesn't need all the time
consuming analogue negotiation when it connects.
In theory it should be really simple to use; just configure ppp as if you were
connecting to a serial modem. gsm0710muxd or equivalent may complicate this
slightly, but I wouldn't expect it to be any worse than the current use of ppp
for GPRS. That said, I haven't tried it.
While GPRS is faster CSD has other advantages which may be critical in some
cases. You can call into it, which may not be possible with GPRS as it is
often hidden behind NAT. CDS also has lower, predictable latency whch made it
the transport of choice for a GSM cryptophone.
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