What is VoIP (Voice Over Internet Protocol)?

To improve everyday and business communication, try VoIP because VoIP transfers sound via Internet Protocol. In the following sections you can read about the definition of protocol, how VoIP works, what advantages it has, what it can provide you and what kind of equipments are needed to be able to use VoIP service.

VoIP is a technology that allows you to make telephone calls to another computer or telephone via the Internet that offers great quality. VoIP uses the Internet to transmit calls and uses codecs for converting analog voice signals into digital data. The sent signals are cut into smaller packets according to the size of IP packets that are put together and converted back on arrival to the destination.

In Figure 1 you can see how a VoIP call is built up. If you initiate a call from a VoIP or a softphone that first connect to your Ozeki Phone System and they use the Internet to transmit the call to a VoIP phone or a PSTN (Public Switched Telephone Network). The communication channels are built up by the Session Initiation Protocol (SIP).

ozeki phone system what is voip
Figure 1 - A VoIP Call through Ozeki Phone System

Protocol, Internet Protocol - definitions

A protocol is a set of rules that regulates data transmission among computers. When two or more computers are connected, they send the data compressed into data packets. These packets are similar to postal packs: they must be addressed according to the regulations of the postal system in order to get to the addressee. The different protocols can be imagined as the postal systems of different countries: different countries need different information to be able to deliver the packs.

The Internet Protocol (IP) is the protocol that is used for transmitting data packets via the Internet. Each computer connected to the Internet must have a unique IP address to be able to send and receive the data packets.

How it works

VoIP supports real-time communication that means voice packets are delivered immediately.

A VoIP phone always needs an adapter to connect to a network. In order to be able to receive calls on your computer or phone you need to have a phone number.

VoIP technology is based on the H.323 standard. This standard defines the rules how video and voice data are transmitted through IP. If you would like to know more about this standard, please read our page: What is H323?

Advantages of VoIP

The VoIP has many advantages that usually simple telephones cannot provide. Usually there is no additional charge beyond the Internet access.

  • Saves Your Money
  • As VoIP uses a protocol to initiate calls and it is usually cheaper than traditional phones because if you make a call to another country it goes through a VoIP channel and you only have to pay for the local tariff.

  • Provides the communication with Multiple Persons
  • It allows you to talk to more than one or two person at the same time on one line since it can deal with the mass of the incoming data packets. With VoIP you can also make conference calls.

  • Flexibility
  • You can connect to a VoIP provider worldwide if you have a fast and stable Internet connection.

  • Interesting and Useful
  • VoIP has many useful features like :

    • Voicemail
    • Call blocking
    • Call waiting
    • Call forwarding
    • Anonymous call block
    • Return call


  1. Better efficiency
  2. Lower phone costs
  3. Increase in productivity (If the workers can call each other free they can work more efficiently)
  4. Possibility to connect to PSTN

Equipments needed

You are required to have a broadband Internet connection. You need to have a computer, a VoIP telephone or a traditional phone that requires an adapter. If you call someone, that person only needs a telephone.

VoIP providers

VoIP providers are necessary to make and receive calls. They connect different local phone numbers in different cities to a telephone system. VoIP service providers usually offer better sound quality than PSTN systems. The lack of coverage is not a problem in VoIP systems, or you can connect to the system worldwide if you have Internet access. Here you can read about the VoIP providers.

Corporate use

VoIP is spreading among businesses because it provides lower phone costs. Any kind of businesses can use VoIP whether they are small or large.

The Ozeki Phone System is the best option if you would like to exploit the advantages of the Voice over IP technology. Ozeki Phone System is a VoIP PBX system that is easy to setup, configure and it takes a very little effort to maintain. It is the perfect choice to be used as the central node of your VoIP system.

To understand VoIP better read the following topics as well:

If you became interested in this topic, please watch our video:

What is VoIP? (Video tutorial)

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