Learn how to set up and use Wi-Fi calling, the E911 address, and the connection preference on the Microsoft Lumia 640.
Turn on & connect
To use Wi-Fi calling, you must first register an E911 address and turn on Wi-Fi to connect to a Wi-Fi network.
- Register your E911 address at My T-Mobile.
- Turn on Wi-Fi.
- From the Start screen, touch the screen and slide left.
- Scroll down to and tap Settings.
- Tap Wi-Fi.
- Tap the Wi-Fi networking switch to turn it on. Your phone automatically scans for available networks.
- Tap the desired network.
- If security is enabled, enter the password, then tap done.
Set connection preference
- rom the Start screen, touch the screen and slide left.
- Scroll to and tap Settings.
- Tap cellular+SIM.
- Tap SIM settings.
- Tap Calling preference and select one of the following:
- Wi-Fi preferred
- cellular preferred
- Wi-Fi only