The way an incoming call appears depends on your Preferences for incoming calls and the OS of your device.
On devices running OS 7 or lower, the incoming call screen depends on whether Settings > Preferences – Notifications > Use heads-up display for incoming calls is enabled.
If you do not have heads-up notifications enabled, the incoming call is displayed on the full screen. When UniTel Voice is in the background and you receive a call, UniTel Voice is automatically brought to the foreground. When UniTel Voice is locked, the call answer screen appears.
If you have heads-up notifications enabled, a notification floats down from the notification bar and presents you with your call answering options. If you want to see the full-screen incoming call notification, tap the heads-up notification.
On devices running OS 8 or higher, you are always presented with the heads-up notification for incoming calls.
Some devices running Android Oreo only support text tones and not ringtones in Android notification channels. When you install UniTel Voice, the default ringtone is set to a custom distinct ringtone. If you are using a device that does not support ringtones and you choose a text tone, you can only go back to the UniTel Voice distinct ringtone by reinstalling UniTel Voice.
For Xiaomi MIUI 10 devices, you may need to Enable Sound in the native Android OS settings.