Repeat callers is a feature that has been added to the Do not disturb option in Android™ 6.0 or higher. It allows your Xperia™ device to sound if the same person calls a second time within 15 minutes.
Android™ 6.0 or higher
To enable Repeat callers
- Drag the status bar downwards, then tap Do not disturb.
- Find and tap MORE SETTINGS > Priority only allows or Allowed in Priority only.
- Drag the slider beside Repeat callers to the right.