PioneerPOS G24-LC 用户手册

This command enables the ME to perform the actions necessary for establishing communication 
between the terminal and the external Packet Data Network (PDN).

The ITU V.25ter 'D' (Dial) command causes the ME to enter the ITU V.25ter Online Data state 
and together with the terminal, to start the specified layer 2 protocol. The ME returns CONNECT 
to confirm acceptance of the command prior to entering the ITU V.25ter Online Data state. No 
further commands may follow on the AT command line.

The detailed behavior after the Online Data state has been entered is dependent on the PDP type, 
and is described briefly. GPRS attachment and PDP context activation procedures may take place 
prior to, or during the PDP startup if they have not already been performed using the +CGATT 
and +CGACT commands.

When the layer 2 protocols have terminated, either as a result of an orderly shut down of the PDP 
or an error, the ME enters the ITU V.25ter command state and returns the NO CARRIER final 
result code.

If <called address> is supported and provided, the ME automatically sets up a virtual call to the 
specified address after the PDP context has been activated.

If <L2P> and <cid> are supported, the +CGDCONT, +CGQREQ and other such commands may 
then be used in the modem initialization AT command string to set values for PDP type, APN, 
QoS and so on.

If <L2P> is not supported, or is supported but omitted, the ME uses a layer 2 protocol appropriate 
to the PDP type.

If <cid> is not supported, or is supported but omitted, the ME attempts to activate the context 
using one of the following:

Any information provided by the terminal during the PDP startup procedure. For example, 
the terminal may provide a PDP type and/or PDP address to the ME.

A prior knowledge, for example, the ME may implement only one PDP type.

Using the "Empty PDP type" No PDP address or APN is sent in this case and only one PDP 
context subscription record is present in the HLR for this subscriber.

This command may be used in both normal and modem compatibility modes.