How to open and close PDP Context ?

PDP Context

First, attach to the GPRS network by sending the command:

AT+CGATT=<state>

The execution command enables the MT get attached to or  detached from the
GPRS service.  After the command has completed,  the  MT remains in V.25ter
command state. If the MT is already in the requested state, the command is ig-
nored and the OK response is returned. Any  active PDP contexts will be auto-
matically deactivated when the attachment state changes to detached.

<state>
indicates the state of GPRS attachment

Values:
0  detach(ed)
1  attach(ed)

-----------------------

Next, define a PDP context:

AT+CGDCONT=<cid>, <PDP_Type>, <APN>, <PDP_Addr>

This command specifies PDP context parameter values for a PDP context
identified by  the (local) context identification parameter, <cid>.  A special
form of the set command, +CGDCONT= <cid> causes the values for con-
text number <cid> to become undefined.

<cid>
This PDP Context Identifier is a numeric parameter
which specifies a particular PDP context definition.
The parameter is local to the TE-MT interface and is
also used in other PDP context-related commands. If
no cid is given, nothing will be changed (neither
context definition nor undefinition)

<PDP_Type>
Packet Data Protocol type is a string parameter which
specifies the type of packet data protocol:

Values:
IP    Internet Protocol (IETF STD 5)


<APN>
Access Point Name is a string parameter (framed by
quotation marks) which is a logical name that is used
to select the GGSN or the external packet data net-
work. If the value is null or omitted, then the subscrip-
tion value will be requested.

<PDP_Addr>
String parameter that identifies the MT in the address
space applicable to the PDP (e.g. IP V4 address for
PDP type IP). If the value is null or omitted, then a
value may be provided by the TE during the PDP
startup procedure or, failing that, a dynamic address
will be requested.


-----------------------

Now, active the PDP Context:


AT+CGACT=<cid>,<state>

This command is used to activate or deactivate the specified PDP con-
ext(s). After the command has completed, the MT remains in V.25ter com-
mand state. If any PDP context is already in the requested state, the state
or that context remains unchanged. If the MT is not GPRS attached when
he activation form of the command is executed, the MT first performs a
GPRS  attach and then attempts to activate the specified contexts. If no
<cid>s are specified the activation/deactivation form of the command acti-
vates/deactivates all defined contexts.

<cid>
PDP Context Identifier is a numeric parameter which specifies
a particular PDP context definition. The parameter is local to
the TE-MT interface and is used in other PDP context-related
commands.  

<state>
indicates the state of PDP context activation

Values:
0  deactivated (this is the default for new defined contexts)
1 activated  


That's all.

Now you can query after your IP address by issuing the command:


AT+CGPADDR=<cid>

<cid>
a numeric parameter which specifies a particular PDP
context definition (see +CGDCONT command).



EXAMPLE:

AT+CGATT=1
OK

AT+CGDCONT=1,IP,"internet.netcom.no"
OK

AT+ACT=1,1
OK


Hope this helps some..

- arvep