Data call (aka CSD) with QtExtended

Ed Kapitein ed at
Sun Mar 22 14:10:28 CET 2009

Hi Tuan :-)

well, it seems like you are almost there.
you can check if the gsm network has data capabilities with the
following command:


+CBST: (0-7,12,14,65,66,68,70,71,75),(0),(0-3)


i am able to make a call  after that with:
ATD xxxxxxxxxx

the username/password i need is indeed my username/password for my
dial-up ISP, but it is only needed *after* a successful call to my ISP.
after a successful login i should be able to start a ppp link with my ISP.

If  i make a datacall to my home phone, i can hear the FR trying to
initiated a data connection, kind of like a calling fax machine.
So you could test that.

A good source of information on ppp could be
I use no PIN, but i don't think that matters much.

Good luck, i will try to make a full internet connection once i have my
username password and let you know the results.

Kind regards,

Tuan TRINH wrote:
> Hi Ed,
> My name is Tuan :-)
> Thanks for your reply, but I still confuse on username/password
> portion, what does it for? For connecting to operator's modem ?
> I don't have any idea on how data calls are established end-to-end.
> Where does ppp play its role? Do you have any doc or URL regarding it ?
> I did the following commands but nothing happend:
> ATE1
> AT+CPIN="yyyy"
> AT+CBST=0,0,1
> AT+CR=1
> ATDxxxxxxxxxx
> where yyyy is my PIN and xxxxxxxxxxx is another phone number. After
> last command I also repeat some AT+CEER to check but it reports "no
> error" as:
> +CEER: 0,1,1,255,no error
> With the first 4 ATs, I can make a voice call successfully.
> Cordially,
> Tuan
> On Sun, Mar 22, 2009 at 6:23 PM, Ed Kapitein <ed at
> <mailto:ed at>> wrote:
>     Tuan TRINH wrote:
>     > Yes, my GSM carrier support both data/fax and I also did
>     register it.

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