What's using this data when I'm on WiFi?

[GFSarah]

Forgive the seemingly dumb question (or maybe it really is dumb, I don't know), but what exactly uses the iPhone's data plan when it's connected to WiFi? And no, I'm not talking about calls and texts; I know those are data -- not WiFi transmissions, and they are reported as calls and texts anyway. I know voicemails are data usage and are not ever routed through WiFi.

The reason I ask is that after all this mess about the new data plans, I've paid close attention to my data usage in just the last two days to see exactly what activities use how much data. There are 4 items billed as data usage when I was definitely on WiFi and should not have had any of the iPhone's data being used. There were no voicemails being left or retrieved at those times and for the life of me, I can't figure out what that data usage is for.

Any ideas? What sort of apps or whatever else would go through the data network instead of WiFi?

 

[GFSarah]

I see there's a similar thread to this now ("Mysterious Data Trasfers"), but just to re-iterate, I'm asking about data that goes over the iPhone data network when WiFi is connected and turned on. Thanks.

 

[Daiden]

How much data? Your phone should still communicate with AT&T's cellular towers, but the usage shouldn't be very high.

 

[GFSarah]

It's not much ... anywhere between 40kb and 1mb. Still though, it totaled just shy of 2mb in one day, and if it held steady, it would be 60mb in the course of a month. I know it's not much, but it concerns me not just as a evaluate the usefulness of the new plans to myself, but more because I don't know what it is or why it's happening.

 

[ngenerator]

Is there a chance your phone was locked (off, but not turned off) and emails were pushed or looked for? That's the only thing I can assume it would be, because then it wouldn't be via wifi if the phone was locked (unless you're jailbroken w/ Insomnia).

 

[brdnboy]

I think one of the many reasons that the iPhone requires a data plan is that the OS is built to always have a data connection (not Wi-Fi). When the phone is locked Wi-Fi is disabled to save battery and any push or fetch functions for MMS, email, voicemail, etc. still occur. They occur over Edge or 3G and this may be where you are seeing this data transfer from.

 

[GFSarah]

Just checked everything and I received an email around the time of one of those "unknown data" incidents, but not so for the others. I have MobileMe pushing, so there should be no checking on the part of the phone. After MUCH thought, I think at least two of the times occurred while I was actually using the phone, so whether initiated by me or an unknown party, the phone was not asleep and should not have defaulted to doing anything over the data network when it was definitely on WiFi.

I'm doing a little experiment right now ... the two times I identified that I was using the phone (on WiFi) and saw data charges, I believe I was using two particular apps both times. Today I've used the two in question at the same time, then one by itself an hour later, and then the other by itself an hour after that (all this while on WiFi of course). Hopefully I'll see another data usage pop up that I can trace to a certain app (or both). This is going to bug me until I figure it out.

Thanks for the input to those who have posted.