What is Voice over Internet Protocol (VoIP) and how does it work?

How does Voice over Internet Protocol (VoIP) work?

VoIP allows subscribers to make telephone calls using a computer over a data network like the Internet. VoIP services convert your voice into a digital signal that travels over the Internet. If you are calling a regular phone number, the signal is converted to a regular telephone signal before it reaches the destination.


One way to make a VoIP call is to pick up phone and dial the number, using an adaptor that connects to high-speed Internet connection. The phone call goes over the Internet to the called party’s local telephone company for the completion of the call. Many VoIP plans allow users to talk for as long as they want with any person in the world. One can also talk with many people at the same time without any additional cost.


  • A broadband connection is preferred.
  • A microphone plugged into a computer can be used. The number is dialed using the keyboard and is routed through your cable modem.
  • Calls can go to normal landline, cellphones and other VoIP phones in any city anywhere in the world.
  • Some VoIP providers charge for long distance calls to numbers outside the calling area, similar to traditional telephone services. Other VoIP providers permit calls to anywhere at a flat rate for a fixed number of minutes. VoIP providers may permit users to select an area code different from the area in which they live.
  • Some VoIP providers offer their services for free, typically for calls to other service subscribers.


What is Voice over Internet Protocol (VoIP)?

Voice over Internet Protocol (VoIP, Voice over IP) is a general term for a family of methodologies, communication protocols, and transmission technologies for delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. Other terms frequently encountered and synonymous with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, and broadband phone.

VoIP, or Voice over Internet Protocol, is a method for taking analog audio signals, like the kind you hear when you talk on the phone, and turning them into digital data that can be transmitted over the Internet.

VoIP can turn a standard Internet connection into a way to place free phone calls.

There are three different “flavors” of VoIP service in common use today:

ATA — The simplest and most common way is through the use of a device called an ATA (analog telephone adaptor). The ATA allows you to connect a standard phone to your computer or your Internet connection for use with VoIP. The ATA is an analog-to-digital converter. It takes the analog signal from your traditional phone and converts it into digital data for transmission over the Internet.


IP Phones — These specialized phones look just like normal phones with a handset, cradle and buttons. But instead of having the standard RJ-11 phone connectors, IP phones have an RJ-45 Ethernet connector. IP phones connect directly to your router and have all the hardware and software necessary right onboard to handle the IP call. Wi-Fi phones allow subscribing callers to make VoIP calls from any Wi-Fi hot spot.


Computer-to-computer — This is certainly the easiest way to use VoIP. You don’t even have to pay for long-distance calls. There are several companies offering free or very low-cost software that you can use for this type of VoIP. All you need is the software, a microphone, speakers, a sound card and an Internet connection, preferably a fast one like you would get through a cable or DSL modem. Except for your normal monthly ISP fee, there is usually no charge for computer-to-computer calls, no matter the distance.


Vocaltec developed the first Internet Telephony application just a few years ago. It let two multimedia PCs (microphone, speaker, sound card, modem or Network Interface Card) serve as a kind of telephone. This new kind of telephone required an Internet network connection instead of the traditional Public Switched Telephone Network (PSTN). This PC to PC Internet Telephony let people communicate cheaply (no per minute charges). However, these early systems were not as convenient or of the same sound quality as conventional telephone calls. Many of these issues are being resolved with newer technology and the use of private networks with stricter Quality of Service (QoS) controls.


The next step allowed one person to use a multimedia PC as a IP based telephone (either connected to a LAN or to an Internet Service Provider via a modem) to dial a person with a conventional telephone. This involved the an Internet Telephony Gateway to be in the geographical region of the person with the conventional telephone. This gateway translates the conventional telephone voice transmission to an IP Telephony format.


The most recent step in the development of IP Telephony services is the placement of gateways in multiple geographic areas. This removes the need of a PC on either end of a conversation. The use of private networks instead of the public Internet as well as specialized equipment to reduce some of the sound quality problems associated with IP Telephony makes telephone-to-telephone communications a viable alternative to traditional telephone calls.


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