Confused about mobile data, data roaming

[Omar91]

I just got my Nexus S and in the network settings there are two options. One "Data enabled" (Enable data access over Mobile Network). Then there are Data roaming "connect to data services when roaming).

What's the difference between these two options? I know that I can't use 3G without roaming, and MMS won't download, s

 

[sitlet]

Data enabled just means that your 3g radio is on, thus enabling you to use data. If the data roaming box is checked, it will let you use data, IF you are roaming. However depending on what carrier you are on, you could be charged a lot of money to use data while roaming.

Is it possible to recieve mms without roaming enabled??

Regular text messages DONT use data. However, if you are trying to receive a picture/video text message, that will require data to download that file.

 

[takeshi]

I know that I can't use 3G without roaming

That's incorrect. Roaming is not required for 3G. Roaming only matters when you're on another carrier's network. If you only use your carrier's network then roaming isn't relevant.

Data enabled, however, is required for data whether you're roaming or not.