SL8082T problem with GPRS connection

Hello, I use a shield for raspberry pi based on the SL8280T module (http://snootlab.com/lang-en/snootlab-shields/834-shield-airpi-v09-for-raspberry-pi-2g-3g-and-gps.html). The final aim is send xml file via SFTP and 3G.
But the at command “atd*99” returns “NO CARRIER” when I try to connect to the gprs network.

There, the atcommand process :

at+WGRPS=9,2
+WGPRSIND:1
OK
at+CGDCONT=1,“IP”,“free.fr
OK
at+cgatt?
OK
at+cgact=1,1
OK
atd99***1#
CONNECT 115200
iuytejjbsdhsdoiuciuuj("i-e(kj-h"l’kjjrz’zrmorj … (ppp frame?)
NO CARRIER

Where is the problem ?

It looks like you run these commands manually. To be able to use a ppp connection you need to use a tool in the host CPU to setup the ppp connection. Here is an example under Linux:
http://www.acmesystems.it/ppp

https://forum.sierrawireless.com/t/faq-forum-wiki/3491/9