Defines Secondary PDP Context, reads Secondary PDP context state, and
changes Secondary PDP Context.
at+cgdscont=?
+CGDSCONT: (1-24),(2,3,21,22,23),"IP",,,(0-3),(0-4)
+CGDSCONT: (1-24),(2,3, 21,22,23),"PPP",,,(0-3),(0-4)
+CGDSCONT: (1-24),(2,3, 21,22,23),"IPV6",,,(0-3),(0-4)
+CGDSCONT: (1-24),(2,3, 21,22,23),"IPV4V6",,,(0-3),(0-4)
AT+CGDSCONT=<cid>, <p_cid>, <d_comp>, <h_comp>, <im_cm_
signalling_flag>
=<cid>, <p_cid>, <d_comp>, <h_comp>, <im_cm_signalling_flag>