Is your iPhone sending data each time you complete a call?


macrumors newbie
Original poster
Nov 20, 2011
Miami, FL
I am still on an "unlimited" data plan and never paid much attention to how much data I use though it had usually been around 150 MB/month.

So when it was time to convert my wife to an iPhone 4 from a BlackBerry, it seemed to make sense to only get the 200MB data plan - she was averaging at under 10 MB of data usage on her BlackBerry.

Well, she ran ran over by 12MB the first month - in 3 weeks. In the first 6 days of the new (current) billing cycle she had already used over 40 MB. I felt that was a bit much, especially since she uses the device to text message, check email and phone - nothing else.

I figured email is the culprit, viewing PDFs (new freedom, yay) etc. I checked her usage one morning and saw that she had just used 25 MB in an hour while at home and on WiFi!!! Email would be going over WiFi. I checked and she had not sent anything nor received/viewed large emails. I was able to rule out email. I then turned my focus to iMessage. Maybe iMessage is sending huge amounts of data versus SMS? So I disabled iMessage. This was also not the cause.

All I know that on the AT&T website, the data usage is always SENT from the phone.

I then compared her phone calls to those data usage charges and guess what? Each time my wife completed a call, there was a subsequent data transaction SENT from the phone. It is always at least 6 KB, but on occasion several MB!!!!!

Is this normal? I have never heard of such a thing. I also compared my calls and it is true for me as well. (I have an iPhone 4S.)

Give you an example:
Yesterday I called someone as a test. The call duration was 7 seconds. And my phone SENT 764 KBs.
Day before I called my wife at 6:34, we talked for 9 minutes, immediately after my phone SENT 276 KBs.
45 minutes before that I called my wife and hit her voice mail and hung up. Call duration was 3 seconds. Immediately after my phone sent 314 KBs.

I could go on and on. All the above data is from the recent usage page on AT&T's site and almost all instances (except when I was actually using data, i.e. browsing, email) of data being SENT happen after a phone call completes.

Due to the whole battery fiasco I have been paying a lot of attention as to what apps are running. I close my apps and then also remove/close them via the fast app switcher.

I called AT&T and the first rep (who refused to give me his full name after I called his BS) told me that one should always turn off one's smart phone once a day for at least a minute as the connection degrades after a while, leading to dropped calls etc. I never heard that in my life, but he assured me he's been telling customers this for 14 years!! He also pointed out that one should turn off cellular data when around wifi networks. I asked him if this is in writing anywhere or what he is basing these "suggestions/resolutions" on. He had none. I asked him for his name, he wouldn't give it and so I asked for a manager.

I was transferred but again, received the advice to turn of cellular data if I want to avoid data charges. I made it clear to the person that I do expect to be using data, I just don't know why it would coincide with every single phone call my wife makes (and I for that matter).

Why would I need to click 4 times to turn of cellular data if this is sooooo recommended??!?!?!?!?! Wouldn't it be more accessible? Or why wouldn't the phone do so automatically?

Anyway, I am obviously not satisfied with those suggestions. In fact, it is scary. Imagine others going over their 200 MB plan because of this?

I think this might be an iOS5 thing but not sure. I just can't see a random app doing this. Any ideas? Have you checked your AT&T data usage and compared it to your calls?

I can provide more data if needed.


macrumors 6502
Jan 21, 2008
Wow, that's a long post! :eek:

My wife and I have 4S's and we see extraneous data usage all the time. It's actually driving me crazy. We were told by AT&T to turn off our cell phones when not in use. When we pointed to the idiocy of the suggestion she said you're right, that's not feasible. So then she suggested we turn off 3G when we're near wifi. Again I told her the suggestion was stupid since never before had we seen so much 3G data usage when we're connected to wifi. She agreed and then had no further suggestions other than return our iPhones (ha!).

Same thing at apple store. After talking to their geniuses they concluded that we could either return the phones or turn off 3G when near wifi.

In essence, nobody we've talked to could explain the constant 3G data usage when on wifi. So, I've been doing some research. Your observation of seeing data after each call I'm not sure I've noticed that yet. However, I do believe that the phone falls back to 3G as soon as the phone locks, regardless of whether it's charging or not. This is definitely new behavior as before the phone (my previous iPhones) would stay on wifi if it was available, especially when charging. Not so any more. So if you start downloading apps on wifi, there's a good chance it'll go back to 3G when the phone locks. Or, even worse, if you start Pandora streaming on wifi it too appear to go to 3G when the phone locks. Not good for streamers.

My suggestion is that you file a bug report on I've been pushing everyone that has this (or similar odd data usage) to do the same. Something is way different with iOS 5 and it's now a complete data hog.

wow, my response was equally long! :eek:


macrumors newbie
Original poster
Nov 20, 2011
Miami, FL
Yeah, sorry about the long post. Wanted to set the mood =D

Surprised no one else has made this connection to their data usage, especially since I am seeing it on two devices.

I will take your advice and report this as a bug to Apple, let's see what they think about this.


macrumors 6502
Jul 1, 2009
Do you have iCloud linking to address book it's possible when you access the phone application it each time calls home and checks for any contact updates? may not be related to making a phone call but just the fact you used the phone application?

iCloud is also used to backup data so could be adding to that.


macrumors 68040
Sep 8, 2011
Eureka Springs, Arkansas
I checked her usage one morning and saw that she had just used 25 MB in an hour while at home and on WiFi!!!...
Yesterday I called someone as a test. The call duration was 7 seconds. And my phone SENT 764 KBs.
How are you checking data on a call that happened the same day? When I ham reviewing data usage on the AT&T website, I never see usage from the same day - only the prior day, sometimes only 2 days prior.

Also don't read too much into the "Sent" verbiage. Everything is "Sent" when you look at the detail on, they don't differentiate on Internet/MEdia Net as to what direction the data is flowing.
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