## Phone to phone calls

Voice numbers can call phone numbers on the fixed or mobile phone network. You can rent and configure voice numbers from the Sinch [dashboard](https://dashboard.sinch.com/numbers/overview) by following these steps:

1. Rent a Voice number from the Sinch [Dashboard](https://dashboard.sinch.com/numbers/overview), under the *Numbers* tab.
2. Assign the number to your application. Under the *Apps* tab, select your app and assign the number under the app Voice settings.
3. Configure a callback URL under your app's Voice settings, where Sinch will send call-related events.


When a user calls your configured voice number, the Sinch platform will trigger an *Incoming Call Event* callback towards your callback URL. The destination number - where the call will be connected to - has to be specified in your response to the *Incoming Call Event* callback. Similarly to app to phone calls, the Sinch platform will trigger additional events for call control.

For more information please check the [Callback API](https://developers.sinch.com/docs/voice/api-reference/voice/callbacks). The callback events that are used in phone to phone calls are the *Incoming Call Event* callback, the *Answer Call Event* callback and the *Disconnect Call Event* callback.