You must either setup the GPRS settings on the phone -OR- perform a manual setup for the modem as explained in Part 6 .

Part 3a: Setup op GPRS on the mobile phone. - Nokia

The next step is to setup and enable GPRS on the mobile phone. These instructions are for the Nokia 6820, 6230, but the menu items will be similar for other models.
On Menu-> Settings -> Connectivity -> GPRS -> GPRS connection -> select 'Always Online' (You can always change this to 'When needed' once everything is working

On Menu-> Settings -> Connectivity -> GPRS -> GPRS modem settings
select option 'Edit active access point'

now select 'Alias for access point'

type in a name, this is just a descriptive name and can be anything, but it may be useful to name it so that you know to which network it belongs

now select 'GPRS access point'

Enter the name for the GPRS access point, this you must get from your network provider.

For South Africa, network Vodacom it is: internet
For South Africa, network CELL-C it is: internet
For South Africa, network MTN it is: internet
For South Africa, network Virgin Mobile it is: vdata

It will be something else for your network! It may also be in IP format such as 193.113.200.200

You are done with the setup. On the phone display you'll now see the G symbol, indicating that the GPRS is enabled.

Part 3b: Setup op GPRS on the mobile phone. -Sony Ericsson K750i

For Sony Ericsson K750i the GPRS access point can be configured :
Menu->settings->tab connectivity->internet settings->internet profiles->
edit or create a new profile. If you are creating a new profile, follow the settings below when asked which data account to use.

When asked for "Connect Using", create a new data account:

Connect Using -> New Account -> GPRS data -> Enter an accounts name such as WAP GPRS

The screen should show "New GPRS data". Enter the following values for the settings:

APN: internet
Username:
Password:
Login request: Off
Allow calls: Automatic
IP address: ... [Leave blank]
DNS address: ... [Leave blank]
Authentication: Select only PAP
Data compression: Off
Header compr.: Off

Now press the "Save" button. The screen will show the message "New GPRS account created". Scroll down to the profile you have created and press the "More" button and then select "Settings". Confirm that you have the following values set:
Connect using: [the data account you created above]
Internet Mode: WAP
Gateway Address: For South Africa, Cell-C this is [196.031.116.250]
Security: Off
Username:
Password:

Press the "Save" button. Scroll to the profile you have just created and press the "Select" button. The display will show "New profile created".