The quality of your calls depends on the speed of the wireless connection.
As of August 2011, Wi-Fi calls no longer use up your T-Mobile minutes. Previously, calls placed over Wi-Fi utilized minutes on your calling plan, just like a regular call. If your phone has the Wi-Fi calling app, add the Wi-Fi calling feature through Mytmobile.com or by calling customer service.
Instructions
1. Call T-Mobile at 1-800-866-2453 to add Wi-Fi calling to your plan. It is currently only available for Even More and Even More Plus plans.
2. Pull down the notification bar from the top of the screen and tap the "Wi-Fi" icon to turn it on. Alternatively, tap "Settings," "Wireless and Networks" and place a check by "Wi-Fi."
3. Tap "Wi-Fi Settings" and scroll down to see the networks that are in range. Tap the network and enter the security key if it is a secured network. The key is usually in the instruction manual or found by calling your Internet service provider.
4. Press the "Back" button to go back to the home screen.
5. Tap "Applications" and scroll down to "Wi-Fi Calling."
6. Launch the app and tap "On/Off." The slider turns blue and switches to the On position. A new icon displays in the status bar indicating that the feature is enabled.
7. Tap the phone icon and dial a number as usual. The calls are transmitted through the wireless signal as long as you are within range.
Tags: calling your, Even More, scroll down, Wi-Fi calling