## App to phone calls

Apps using the iOS, Android or Javascript SDK can call phone numbers on the fixed or mobile phone network. For additional call control, you can configure a callback URL under your app's voice settings in the Sinch dashboard, where Sinch will send call-related events. By capturing and responding to these events from your app, you can allow or deny calls to go through. Events will also be triggered when the calls are answered or disconnected.

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 app to phone calls are the *Incoming Call Event* callback, the *Answer Call Event* callback, and the *Disconnect Call Event* callback.