Yes, nice explanation. CSD is used as preferable scenario for transporting crypted voice.<div><br></div><div>Regards</div><div>Mile<br><div><br></div><div><br><div class="gmail_quote">On Wed, May 6, 2009 at 12:31 AM, Al Johnson <span dir="ltr"><<a href="mailto:openmoko@mazikeen.demon.co.uk">openmoko@mazikeen.demon.co.uk</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div class="im">On Tuesday 05 May 2009, Franky Van Liedekerke wrote:<br>
> On Tue, 5 May 2009 22:44:49 +0200<br>
><br>
> Mile Davidovic <<a href="mailto:david.moko.comunity@gmail.com">david.moko.comunity@gmail.com</a>> wrote:<br>
> > Hello<br>
> ><br>
> > My understanding is next:<br>
> > - qt extended have support for CSD but quite rudimentary (these words<br>
> > are from qt extended documentation)<br>
> > - sample qt application works fine with CSD but only first time (they<br>
> > have problem with releasing resources)<br>
> ><br>
> > In general, OpenMoko is capable of working with CSD but my<br>
> > understanding is that CSD (at least on Qt) is not preferable working<br>
> > scenario.<br>
> ><br>
> > Regards<br>
> > Mile<br>
><br>
> Hi Mile,<br>
><br>
> I'm sorry, but I'm not really familiar with CSD calls, could you<br>
> ellaborate?<br>
<br>
</div>Circuit Switched Data, the original GSM data mode where the phone acts as a<br>
slow (9600) conventional modem. Later HSCSD increased the speed a bit by<br>
channel bonding. My k700i will let you select between analogue and ISDN modem<br>
behaviour, handy when calling an ISDN line as it doesn't need all the time<br>
consuming analogue negotiation when it connects.<br>
<br>
In theory it should be really simple to use; just configure ppp as if you were<br>
connecting to a serial modem. gsm0710muxd or equivalent may complicate this<br>
slightly, but I wouldn't expect it to be any worse than the current use of ppp<br>
for GPRS. That said, I haven't tried it.<br>
<br>
While GPRS is faster CSD has other advantages which may be critical in some<br>
cases. You can call into it, which may not be possible with GPRS as it is<br>
often hidden behind NAT. CDS also has lower, predictable latency whch made it<br>
the transport of choice for a GSM cryptophone.<br>
<div><div></div><div class="h5"><br>
<br>
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