For improved connectivity and voice communications, you can enable VoLTE on your phone.
1. Go to Settings.
2. Tap Network & Internet > Mobile network > Advanced.
3. Tap VoLTE and slide the switch to the right.
4. Your device will now be connected to VoLTE for HD calls.
Note: Please be aware this will only be possible if your network is set up to handle VoLTE and if this device is enabled for your network. Contact Cat Phones Support to check if your network is compatible.