AT Commands Reference Manual - wireless netcontrol GmbH

Data Operation
Figure 1-3 shows a Class A mode of operation.
Figure 1-3: Class A Mode of Operation
In order to use the GPRS services, the H24 performs the following (TS 23122-650):
1. PLMN selection.
2. Cell selection.
3. Location registration - by GPRS Attach.
At this stage, H24 is able to receive system information from the PLMN; Initiate a call;
Receive "paging" ; Respond to "paging" ; receive cell broadcast messages.
4. Authentication with HLR.
If USIM - H24 originates "UMTS authentication" (TS 33.102) -
This is a mutual authentication in which NW authenticates H24, and H24 authenticates the
NW.
If SIM - H24 performs "GSM authentication" in which H24 is authenticated by the NW (No
mutual authentication).
5. PDP context activation -
The PDP context contains mapping and routing information for transferring PDP PDUs for
that particular PDP address between the MS and the GGSN.
PDP context can be activated by H24 or by the NW.
1-4 H24 - AT Commands Reference Manual April 15, 2010