3G Data overrides Wifi

the AT&T guy is full of it.

The phone shouldn't lock/sleep when an app is playing unless its not created correctly. I watch youtube all the time and when video is playing it wont shut off.

Wifi will go off temporarily in sleep mode but any additional data coming in will wake the phone and wifi will connect anyway.

Yes, when the phone is in sleep/autolock mode, WiFi turns off to conserve the battery. I don't beleive it's true that Hulu continues to stream when the phone goes to sleep - the phone shuts down the app when sleeping.

If you want to override the WiFi shutdown when sleeping - 2 ways:

1. Leave the phone plugged into power source

2. Settings > General > Network Cellular Data > OFF

Wifi will go off temporarily in sleep mode but any additional data coming in will wake the phone and wifi will connect anyway.

Incorrect. When the phone is in sleep mode, it receives various data - email, push notifications, MMS, iMessage, etc. using cell data and does not wake the phone or restart WiFi

There appear to be duelling stories. I just spent an hour on the phone with AT&T and then Apple tech & tech supervisors. AT&T maintains that when the iPhone goes into "sleep mode," which they defined as the screen going dark, the wifi turns off, all data connections are through 3G and you're charged for the data. The super said it's an Apple thing.

At Apple, the tech said the only solution is to either turn off auto-brightness (wrong) or set phone lock to Never (apparently possible). Her senior tech guy said categorically that the iPhone does not switch off wifi when the screen goes dark, but I don't find any other explanation for my skyrocketing data usage since switching from 4 to 4S two weeks ago. He also recommended changing my router settings to this: http://support.apple.com/kb/HT4199?viewlocale=en_US, which he said solved a problem he had with his iPad losing wifi periodically. He also suggested turning off Cellular Data (Settings > General > Network) to ensure it doesn't switch over.

By the way, my data plan was being charged while the iPhone was plugged into a dock.

Message was edited by: R3ickb

If your iPhone remains connected to a power source while connected to an available wi-fi network, the wi-fi connection will be maintained regardless if the iPhone is in sleep or standby mode.

The wi-fi connnection will not be maintained if the iPhone is not connected to a power source when it is in sleep or standby mode.

As I mentioned, my iPhone was connected to a dock at the time it was racking up huge data charges on at least one occasion. One mitigating factor may be that I usually turned off the screen while it was connected.

As you mentioned with an edit to your original post which was not available when I replied.

The dock was connected to a wall outlet?

Turning off the screen is sleep which should make no difference when the iPhone is connected to a power source while connected to an available wi-fi network as I mentioned - not unless there is something wrong with your iPhone or the dock was/is connected to your computer.

The iPhone was docked to a Sony "Personal Audio Docking System" radio. When it's docked, the charging icon appears on the iPhone screen.

AT&T insisted that "Sleep Mode" means the screen going dark, at which point, they said, the wifi is turned off and the data transfer switches to 3G unless that's not available, in which case it switches to Edge. The Apple tech disputed the wifi turning off on sleep.

In any event, my data usage skyrocketed from a max of 150 MB per month over the past year to 195 MB over 20 days since I switched from iPhone 4 to 4S. And the peak usage amounts coincided with times I was at home, (at least, over this past week) and using the phone to listen to streaming radio.

Whoever you spoke with at ATT is wrong.

I know nothing about the Sony docking system and if it includes the Apple "made for iPhone" certification.

Try connecting the iPhone to the power adaptor included with the iPhone purchase to see if this makes any difference.

The Sony documentation includes a "Made for iPod iPhone" graphic. I think the fact that the iPhone starts charging when connected, and that it plays through the radio from the dock, says enough about that.

There are a lot of discussions about switching from wifi to data plan when screens go dark on the web, across multiple devices, Apple and other. It's hard to distinguish between received wisdom of the responders and actual knowledge, such as that provided by documentation or first-hand participation, but enough people have experienced similar usage charges that there appears to be verification of the dark screen/wifi off camp.

I think there are a bug in the OS since even if my phone is connected to a power source, sometimes it turns to 3G but when wifi is ON after it, it maintains the connection. I never noticed this before, maybe an iOS 5.1.1 bug. I've seen another user with iPhone 4 that had the same issue, and I have a 4S device.

I have been noticing posts that say that a phone stays on wifi while sleeping as long as it is plugged in, and sometimes the post may add as long as it is on wifi and plugged in. Normally when I plug it in for the night it has already been in sleep mode. It displays the slider so I could wake it up, but I normally just put it to sleep without having it finish waking up. So my question now would be, does the phone need to be awake when you plug it in? If it was sleeping when plugged in, does it remain sleeping and stay off wifi? If so, I think this could be an improvement for an iOS upgrade. When it is plugged in I don't see a reason to save battery by keeping wifi off.

On another point, I don't see that screen off necessarily means sleep mode. With streaming audio, such as with Pandora, the screen goes dark but I believe it stays on wifi. You don't hear the click as if it is going into sleep mode though. With an app with video, it might be up to the author of the app. If the videos are a kind that the audio is all that you want, it might be of value to let the screen go dark as with streaming audio in order to save battery power. In that case, the app can keep the phone from going to sleep and data may keep streaming. But it still should be on wifi.

Now for what brings me here: I got a message from AT&T saying that I went over my 200 meg data. I hadn't gotten the early warning messages at 60% or 90% because the problem was all in one day with 190 meg at once. The only time I had high data usage before was when I got iOS5 with iCloud and photostream. I concluded that photostream was probably the problem when I took pictures away from wifi and turned that off. But this was without that and all in one day when I was at home on wifi including the prior day. When I got the message about the overage I checked that wifi was still on in the settings, which it was.

The day that the overage was charged my granddaughter was watching YouTube videos. This four year old girl wouldn't have gone into the settings to turn wifi off and back on later. Probably just a coincidence, but we just started getting 3G signal on this iPhone 4 phone at our house a few days before this. I only have one megabit broadband internet and I was wondering if the phone might revert to 3G if the wifi wasn't keeping up (I was likely also using the wifi with my computer). One reason I have some suspicion about this new signal is that my wife's iPhone 4s started getting 4G signal at this same time and noticed that sometimes it goes from wifi to 4G without going to sleep. My understanding is iOS chooses wifi first, but could it also consider speed? If the cellular data is faster than the wifi, would it choose it?

i know i'm a little late to the thread, but i've had a couple experiences identicle to these.
i got into the iphone market about 2 years ago, picked up a 3gs when they were just $50 and thoroughly enjoyed it. i was on the bare minimum data plan because i honestly dont use it that much and at the time was trying to make the phone bill as cheep as possible.
for the first 4 months i never went over, checked my data constantly, and would turn off 3g and cell data before i got close. then my phone developed a few dead pixels and the lock button started acting funny, but i didnt care too much because it was well within the standard 1 year warranty and they replaced it with no big fuss. within a week of that happening i went over my data limit twice. i called at&t and they said they couldnt tell me what the data was, and the best i could do was go online and look at what time it was, it was about 4am both times. even with as late as i stay up, i was alseep, and the iphone was locked and plugged in to an outlet.

so i got on the forums and started searching for answers and this is about all i found:

-apple and at&t will blame each other and never take responsability.
You will be out about $80 from overage fees, and you cannot tell them to not allow your phone to go over, it violates some potential safety thing, and honestly is just there to screw you over. you arent evel allowed to see what the phones on your plan are sending because it violates some personal security laws, there is NO way to see what information was being sent, what site it was sent to, or if it was even incoming or outgoing. the most you can see is what time it was sent.

-iphones default settings are "use wifi over 3g, unless the wifi is going slow, then supliment with 3g"

i had already turned this feature off, i had come close to going over in the first month i had it because of this feature, so as soon as i got my replacement i went ahead and turned it off. it's an odd feature that i dont like, you can sit there and watch it boot a weak wifi signal for 3g while a video loads, then switch back like nothing happened.
(i'm now using a 4, and i cannot for the life of me find the option to turn off it's suplimental crap, i changed it on my 3gs, but now it's like it never existed)

-when you get a replacement phone, they want to set it up in the store, and they will turn on the periodic notifications to apple without asking you.
this is the part that screwed me over, and there is no way to turn these bad boys off once you set up the phone, the only chance you have is to backup your phone, reset it, run through the setup again, and hope that it dosent switch back over when you restore your contacts and stuff.

-the only way to avoid going over when you are close is to either have you unlimited dataplan grandfathered in (which they will try to turn off on every step of upgrading you phone) or to just turn off the 3g *and*cell*data* that they force you to have if you want to use any smartphone.

so basicly, the iphone is gonna send random 200mb data packets if you ever let an apple tech touch your phone, or just blew through the setup, and the packets will send at really akward hours of the night, almost gaurenteeing you are asleep (that way it wont interupt what you might be doing) so it will push you over if you tried to go cheep on the dataplan, and even if you happen to be away or have your phone lit up to use wifi when this happens, you phone could still magically determine that 3g would be faster and turn off the perfectly capable wifi signal anyway. neither company will take credit for it because they are honestly working together to make it impossible for you to not go over, there will always be a chance, and they are hoping that small chance will scare you into buying 2gb more data than you will ever need.

You can turn off the diagnostic & usage reporting to Apple in your settings. Go to Settings -> General -> About -> Diagnostics & Usage. Choose "Don't Send."

I am not convinced that all that data is caused by the diagnostic and usage reporting. Supposedly, when it is plugged in it should use wifi even when sleeping. My understanding is that the usage that you see posted during the night is an aggregate of usage that had been used during the prior day, rather than posting little bits of usage every time small amounts are used.

I feel my excess usage was during the day while I am around wifi, but I have found that the phone drops the wifi connection once in a while even if I have the cellular data turned off in the phone settings. When that happens I get an unknown error message, and it reconnects. I don't know whether the problem is with my router, or whether it could be phone related (iOS or hardware). The problem happens on two phones that we have, an iPhone 4 and a 4s. So I feel that it isn't likely that two phones started to have problems with hardware at the same time. So is it my router, or something with the iOS.

The uexpected high usage started happening when we started getting 3G service in our area. We previously only had EDGE. It was also about the time of an iOS upgrade. I think the timing of the 3G service is a coincidence, since the phones drop wifi even if cellular data is turned off in phone settings. So it seems like either iOS update related, or a problem with my router.

I just had this crap happen to me this morning

iPhone was sitting on a non apple dock, charging. I'm sleeping until my normal wakeup time at 8:00.

At 7:09am, I get a text from AT&T warning of the 90% level. Then 5 minutes later, I get the next text saying I've hit the 100% level and that all data will now be charged.

So obviously the phone used 3G instead of wifi, which was very strong signal seeing as how the wifi access point is not even 20ft from the phone with only one sheet of drywall at a 0 degree angle. There's no excuse for choosing 3G over wifi.

After more than 5 years, of using iOS, I'm tired of the substandard UI that only focuses on shallow things and doesn't deal with things like this problem where the phone should be miserly managing cell data usage. Googles android OS has a metering option that appears to prevent this very thing from happening.

This mornings overage is the final straw for me to say Goodbye to iOS on my phone. It is high time that Apple's engineering team address its customers and gets this taken care of, or I'll be moving to a Samsung/Android phone.