Open-source and highly reliable for basic SIP calls.
Your server address (domain), username, and password.
Use ://google.com if you face one-way audio issues.
There isn't a single "Fast SIP" file; instead, you download a and enter your Mobilis or provider details: 1. For Individual Users (Softphones)
Mobilis(Algeria) – Set the APN to 'internet' | M2MSupport.net
Download an app like Zoiper , Linphone , or Mizudroid from the Google Play Store or Apple App Store.