Enable data network on the iPad 2 so that you could use data roaming from the neigbouring data network.
The iPad 2 allow you to use data roaming from another network when your current data network is not available for connection. So in which scenario would need to use data roaming? well when you go on travelling and you may go out of your normal coverage region, then you would need to connect to a neigbouring data network to get access to the internet.
Here's how to enable it:
1. Go to the Home screen.
2. Then go to the Setting screen.
3. Select Cellular Data.
4. Then have Cellular Switch to On.
5. If you want to use Data Roaming then switch it to On.
Beware that data roaming can cost you money so whenever you don't need it switch it off.
You can view your account information tapping on the View Account. With the SIM PIN option, if you like could enter the PIN to lock the Micro-SIM card and prevent any un-authorization usage.