[PATCH] Parse +CUSD responses.

[Denis Kenzior]

Hi Andrew,

> > Actually valid_ussd_string will accept just about everything.
>
> Ah true.  However I think we should never try to send a UCS2 USSD - we
> would first need to know that the modem supports this (so a vendor
> quirk set by the plugin would tell us this) and then that the network
> supports this too.

You're absolutely right that we shouldn't, I was just pointing out the need to 
always be paranoid ;)

> > What about the evil set of DCSes which indicate a ISO639 2 character code
> > preceding the message?
>
> The comment refers to this.  I think 27.007 tries to say the modem has
> to take care of this and only give us the actual characters of the
> string.
>
> "-       if TE character set other than "HEX" (refer command Select TE
> Character Set +CSCS): MT/TA converts GSM alphabet into current TE
> character set according to rules of 3GPP TS 27.005 [24] Annex A

So this part really only talks about the modem performing character set 
conversion between GSM and IRA/UCS2/UTF8 or whatever is set by CSCS.  I 
suspect the DCS is simply never looked at by most networks/modems :)

Patch has been applied, with some fixes afterward.  I think this is good enough 
until we find a network / modem that supports this stuff properly.

Regards,
-Denis