Read Time: 5.5 mins. Every business requires a unified communication system for effective and reliable communication. The cloud phone system, also known as Voice Over Internet Protocol (VoIP), is one of the most popular systems. It allows users to make calls over the internet, and you can use it over various devices, including smartphone apps, traditional landlines, and computer software. With a phone system, you can have extensions on your main phone number to reach employees. You only need to install telephony software on your server and connect the phones to the server over your IP network.