Hi Anthony,

> And, I saw "ATD*99#" cryptic command was already used in
> gatchat/gsmdial.c if bluetooth is enabled.
>

This is a legacy operation for entering into data mode.  Refer to 27.007 
Section 10.2.1.1.  It can be used as a shortcut for CGDCONT/CGDATA, and 
it seems that some modems do not implement CGDATA at all.

> Otherwise, why this \0 after ATD*99# ? :)
>

Good spot ;)

Regards,
-Denis