Why is iPhone using cellular data even when I'm on WiFi connection?

[jambog82]

Hi everybody. I'm new to iPhoneForums and the iPhone. I recently got a used att iphone 4 (my first iPhone). Up until now I've had the cellular data turned off in network settings. I turned it on about 8 hours ago before I went to bed. Prior to turning it on I checked the cellular data usage in the settings as well as downloaded a data usage app. When I went to bed my phone was receiving wifi, so I assumed any notifications I received would use my wifi connection. However when I checked my cellular data usage both in the settings and the data usage app. I received about 500KB and sent about 200KB of data. Not a lot I know, but why did it send or receive any cellular data when I'm on a wifi connection? I want to leave cellular data turned on for the sole purpose of being able to use the "Find my iPhone" feature if I would lose it in a place where it wasn't connected to WiFi. Is there a way I can set it to only use cellular data for this reason but to not receive notifications over cellular data? I wouldn't even mind receiving cellular data when I'm not connected to WiFi as usually I am either at home or at work, both of which have WiFi, I just don't understand why my phone is using some cellular data even when I'm on a WiFi connection. Is this normal? I have 3G turned off to extend my battery life, but that shouldn't matter for data usage right? I still get the same amount of data only slower, right?

Also, is there a way to turn cellular data off when it uses a certain amount? The data usage app is supposed to notify me when I reach a certain percentage of my data limit, but doesn't actually disable cellular usage. Does such as app exist that would disable it, or can you set the iPhone to do so? My understanding is that if I would go over my 200MB limit, I get charged by att for another 200MB even if I would only go over by a single KB!

 

[xrayeyes]

http://www.iphoneforums.net/forum/iphone-help-15/iphone-4s-cellular-data-usage-29566/

 

[jambog82]

http://www.iphoneforums.net/forum/iphone-help-15/iphone-4s-cellular-data-usage-29566/

Thanks for the reply, I already had "send dianogstic and usage data to apple" turned off, so it isn't that. I have done what the other thread suggested by closing all background apps and turning off all notifications and location services. Still I am using cellular data while I am connected to WiFi. My concern is why is my phone using cellular data when it is connected to WiFi. I thought that when connected to WiFi ALL data was sent/received via WiFi. The only thing that seems to prevent me from using any cellular data is to turn it off completly. But as I said in my previous post I want to keep it turned on to use the "Find my iPhone" feature which right now I have turned off as well to see if that is what was using my cellular data, which it apparently isn't because I am still getting data usage with it off.

At the rate it is going it using atleast 1MB or more a day. That's 30+ MB per month, when you only have 200MB a month 30 is a lot to be evaperating into thin air.