Turning wifi on- does that turn off 3g

[gjkiii]

I noticed when I turn on my wifi the 3g logo is replaced by the wifi symbol. Does that mean that the 3g is disabled or are they both running at the same time? Thank you

 

[daytonaUSA]

It means it's running only off your wifi connection. That's a good thing as wifi is much faster than 3G. When out of range of your wifi, your 3G signal should come in automatically and the wifi symbol replaced.