End-to-end encryption and privacy controls.
Message and call for free* around the world.
Group conversations made simple.
Say it with stickers, voice, GIFs and more.
Reach your customers from anywhere.
http://dlweb.farafile.ir/file/26189/نمونه-سوال-درس-مدیریت-شبکه-های-مخابراتی-دانشگاه-صنعتی-امیرکبیر