Wifi available. Will it use cellular data?

[iamrawr]

So I got my first ever iPhone and it's the iPhone 4. I have the 200mb plan and I plan to switch cellular data off most of the time if wifi is available to avoid overage. Thing is, with cellular data off, I can't do certain things (ex. Receive picture messages via the Messages app) unless I turn on cellular data. So as long as wifi is available, will my phone still use up cellular data even though it can get data off the wifi? Thanks.
I apologize if I failed to look up any threads on a similar subject. I did a quck search but they weren't really what I was looking for.

 

[Carlanga]

not really...

If you have the phone locked with the screen off and running on battery (I don't think it happens when plugged) the phone will switch to 3g until you wake it up again and I guess if any emails or push notifications or others (skype/whatsapp/any voip app) come in you will be using 3G Data for the moment the phone was locked...

 

[iamrawr]

If you have the phone locked with the screen off and running on battery (I don't think it happens when plugged) the phone will switch to 3g until you wake it up again and I guess if any emails or push notifications or others (skype/whatsapp/any voip app) come in you will be using 3G Data for the moment the phone was locked...

Ohhh. Makes sense. Thanks =)
any additional input is welcome!

 

[Carlanga]

no prob

Ohhh. Makes sense. Thanks =)
any additional input is welcome!

no prob! I don't think the apps will consume a lot of data in sleep mode so maybe that will not be a problem for you as long as you are using the Iphone normal backgrounding features, if you are jb careful with the 'backgrounder cydia app' that you might background something with it and let it run and consume data...

also careful for example if you are using pandora or placetrack (similar to latitudie) or any other app that can run in the background and lock the screen then I think it will consume your 3G data while streaming the music, location data to google, etc (maybe even just leaving an app open and just locking the screen like the map app may consume data?)

I think the best way to know your data usage is to use the AT&T myWireless app (its free) you sign in to your account and can actually see all the data, txt and minutes you have consumed up to that point in the month. (I don't know how fast data the usage is posted, don't think is instantaneous but works...). They are the ones that are charging you the data so is more accurate than the one on the settings on the phone for your 200mb control... The app has also ebills on pdf's with push notifications alerts for them and settings to change your plan on the spot too. I think you should try it with the 3G data ON for the first month and constantly check it on the app to make sure you didn't pass your limit so you can later decide the appropriate monetary action (also MMS are considered normal txt's for billing purposes...don't know if they actually will consume your data too)

 

[iamrawr]

Oh, I see. I wasn't expecting that some apps may consume data while running in the background. thanks for the heads up thanks for the tips