VIVAit Call Business

VIVAit Call Business is a unified communications device for the VIVAit system that enables communication between users via audio/video calls.

Its main features are:
* Audio and video calls with selectable quality
* Multi-party conferencing
* Encryption capability

The device communicates via 3G/4G/5G and Wi-Fi networks and manages memory and battery usage according to the operating system.

FOREGROUND SERVICE DURING ACTIVE CALLS

VIVAit Call Business uses the Android FOREGROUND_SERVICE permission exclusively during active phone calls. This is necessary because:

* Voice/video calls cannot be interrupted or postponed by the system. If Android were to terminate the process during an active call, the connection would be immediately and irretrievably lost.

* The service keeps the audio stream, SIP session, and microphone active for the entire duration of the call, and only for that duration.

* During a call, the user always sees a persistent notification with the caller's name, the elapsed call time, and the Hang Up button. The user can end the call and stop the service at any time from this notification, the call screen, or the lock screen.

* The service only starts when a call begins and stops automatically as soon as it ends. It is never active in the background when there is no call in progress.