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PDP context activation (AT+CGACT)
Before data can be transmitted, a PDP context must be activated. One way to do this is the
CGACT command.
Example:
AT+CGACT=1,<cid>
OK
NOTE
More than one context can be activated. If no GPRS attach has been done before, it
will be done automatically by the AT+CGACT command.
Entering the GPRS data mode (AT+CGDATA)
In order to set the GSM/GPRS modem in the GPRS data mode and activate the PPP
stack, the CGDATA command may be used.
Example:
AT+CGDATA=PPP,<cid>
CONNECT
~ }#+!}!}#} }9}”}&} }*} } }’}”}(}”}%}&µ-r#}#}%-#}%*,~~ }#
When the GSM/GPRS modem has answered with CONNECT, it is in PPP mode and no
further AT commands can be sent to the GSM/GPRS modem until the PPP connection
has terminated. The cryptic letter combination displayed after the CONNECT is the ter-
minal interpretation of the PPP traffic.
NOTE
The activation of the drivers necessary to make a TCP/IP connection has to be initi-
ated by the OS. It is the user’s responsibility to adapt the software accordingly and
provide the appropriate drivers.
Modem compatible PDP context activation
No preceding PDP context activation
The series of discrete AT commands can be replaced by the ATD command.
Example:
ATD*99#
CONNECT
~ }#+!}!}#} }9}”}&} }*} } }’}”}(}”}%}&µ-r#}#}%-#}%*,~~ }#
Preceding PDP context activation
If setting up a call with defined QoS and PDP context parameters, the following AT
commands can be used as described in “Discrete PDP context activation”.
Example:
AT+CGDCONT=1,IP,volume.d2gprs.de
OK
AT+CGQREQ=1,3,4,3,0,0
OK
ATD*99***1#
CONNECT
~ }#+!}!}#} }9}”}&} }*} } }’}”}(}”}%}&µ-r#}#}%-#}%*,~~ }#
