Question 1

Does VoIP require an internet connection?

Accepted Answer

Not always. VoIP requires an IP network path between your phone and the system that handles its calls, and that path can be public or private. A call can cross the internet, run over a private connection to your provider, or stay between two phones inside one building. Which of those your calls use depends on how the service is set up. To call ordinary phone numbers, the call also has to reach a service connected to the public telephone network.

Question 2

What type of internet connection do I need for VoIP?

Accepted Answer

VoIP doesn't require a particular type of connection. It needs an IP connection that reaches your voice provider with room in each direction for the simultaneous calls you plan to support, on top of everything else the connection carries. One call takes about a tenth of a megabit each way, so fiber, cable, DSL, fixed wireless and mobile data can each be that connection when they have the room. The decisions left are how much upload is free when the office is busy, and whether your calls cross the public internet or stay on a network your voice provider runs.

Question 3

How much bandwidth does a VoIP call use?

Accepted Answer

Cisco's published calculation puts a VoIP call using the G.711 codec at 87.2 kbps in each direction, and a call using the compressed G.729 codec at 31.2 kbps. Both figures count Ethernet framing and assume the audio is sent in packets that each hold 20 milliseconds of speech. A different codec, packet size or type of link gives a different number, and some links add overhead of their own. So the useful thing to know is how the figure is built.

Question 4

Do I need a phone line for VoIP?

Accepted Answer

No. VoIP doesn't need a traditional analog phone line or the phone company's dial-tone service. It needs a data connection and a device or app that can place calls over it. To call ordinary phone numbers, you also need a VoIP service that connects to the public telephone network. The confusion comes from the word "line," which can mean the wire into the building or the phone service sold on it.

Question 5

What is VoIP?

Accepted Answer

VoIP, short for voice over Internet Protocol, is the group of technologies that carries a voice call as data over an IP network. The term describes how a call travels. It doesn't describe a product, so two services sold as VoIP can have little in common beyond that.

Question 6

How is VoIP different from a landline?

Accepted Answer

A traditional landline carries your voice as an electrical signal on a pair of copper wires that the phone company runs to your building. VoIP carries your voice as data over a network connection, and you reach the service through an account instead of one particular wire. That's the difference when "landline" means the old analog line. Many phones sold as landlines today are VoIP underneath, so the first thing to settle is which kind of landline you mean.