When iPhone goes into "sleep" mode does WiFi go off?

[RetiredInFl]

I have noticed that whenever I "wake" the phone using the top button when the screen first comes on it always says 3G then jumps to the Wi-Fi symbol. My 3GS did the same thing. Is the phone actually in 3G instead of wi-fi when the screen times out or is that just a "cosmetic" issue with the 3G symbol?

It does receive emails in that "sleep" state. I kind of doubt it or it would be using DATA because it could jack up your data use unnecessarily grabbing pushed email.

 

[Zcott]

Wifi gets turned off while it's asleep but when the phone checks for mail it'll turn on wifi, check for mail, then turn off wifi while it's asleep. So the answer is "sort of".

 

[RetiredInFl]

Wifi gets turned off while it's asleep but when the phone checks for mail it'll turn on wifi, check for mail, then turn off wifi while it's asleep. So the answer is "sort of".

Interesting. What if email is being pushed to the phone rather than pulled ? With a pull I can understand it because it's a timed event.

I ask because I rarely if ever INTENTIONALLY use data on a 3G connection and I've used 150megs of my 200 in less than 3 weeks. Looking back a year on my data usage with my 3GS and Android (for 1 month) I've never gone over 160 megs in a month (and that's when I had unlimited data). I figured I was safe with the 200 meg plan.