GPRS
4-20 AT Commands Reference Manual June 30, 20 08
Using the ATD* Command Set
Request GPRS service 'D':
ATD*99***(CID)#
The CID (Context ID) includes the APN (defined by the AT+CGDCONT command) to which
you want to be connected. This depends on the ability of the SIM card to be attached to the
different networks.
The format ATD*99# may also be used. In this case, the G24 will first try to activate a non-empty
(predefined) CID. If the attempt fails, the G24 will try the next CID, and so on.
Note: When buffering the terminal message, data in the G24 (both inbound and outbound data),
the following apply:
Turning off the G24 clears any buffered data.
Removing power from the G24 clears any buffered data.
Whenever the terminal drops the PPP connection with the G24, via LCP terminate, the
buffered data is cleared.
Whenever the G24 drops the PPP connection with the terminal, with LCP terminate,
the buffered data is cleared. LCP termination triggers the termination of the data in the
G24 buffer.
Whenever the G24 drops the PPP connection with the terminal, without an LCP
terminate, the buffered data is cleared. Dropping the DTR also clears the buffer.
When the network sends a deactivation message or a detached message, the G24 buffer
is cleared.
When the G24 transfers data in the uplink and GPRS coverage is lost, the data may
flow-off. If the mobile has lost coverage and is unable to send the packets from the
terminal to the network, the buffers will continue to store the packets until the buffers
are full. The terminal will then be flowed off and the packets will be stored until they
can be sent to the GPRS network.
The amount of time that takes before the user is notified is speci fied in the T3312 timer
that is located in the mobile side. The default delay time of T3312 is 54 minutes, as per
the GSM 0408 specification. After 54 minutes, the G24 deactivates the PDP session.