Zte ZMAX User Manual page 65

To configure your phone to receive Internet calls:
By default, your phone is configured to make Internet calls, but
not to ensure that you will receive them. But you can configure
your phone to listen for Internet calls made to an Internet calling
account you added to your phone.
1. Touch the Home Key > > > Settings > Accounts.
2. Check Receive incoming calls. Checking this setting will
reduce your battery life between charges.
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