Learning VoIP Lingo – Common Definitions in the World of VoIP

While you may know a bit about VoIP by now, there are still many more keywords that are tossed around in the VoIP community. I’m here to help you sort through that, so when someone says to you “oh it sounds like you need an ATA” or “how do you feel about using a softphone” you’ll know just what they are talking about. Think of this as a nifty guide that you can reference whenever you get confused with VoIP terminology. I’ve broken the definitions down into a few different categories: The Basics, Service Related Terms, and VoIP Accessories.


The Basics:

VoIP (Voice over IP)

Let’s start with the reason you’re here – VoIP. The abbreviation stands for Voice over Internet Protocol, which means delivering voice over an internet connection. This technology allows you to have phone service anywhere in the world as long as you have a high-speed Internet connection.

PSTN (Public Switched Telephone Network)

The term used for the international telephone network that carries analog voice calls. The PSTN provides traditional Plain Old Telephone Service (POTS), also known as “landline phone” service, to residences and businesses.

POTS (Plain Old Telephone Service)

Commonly used term to  describe the bare bone dial tone feature provided by most analog phone service providers. POTS has been around for over 100 years and is the basic form of residential and business telephone service in most parts of the world.

VoIP PBX (Private Branch Exchange)

Standard PBX operates as a connection between the PSTN and a business’s internal telephones, fax machines and extensions. VoIP PBX provides similar services but through a company’s data network rather than the PSTN. Basically, PBX is the system that controls everything related to your phones.

PoE (Power over Ethernet)

Power over Ethernet is a technology which allows a single cable to provide both data connection and electrical power.  This technology is useful for powering IP telephones or network cameras where it would be costly to run power separately. It also minimizes the amount of cables needed and eliminates the need to install extra outlets.


Service Related Terms:


A term used to define high speed Internet connection. Bandwidth is the amount of data that can be transmitted in a fixed amount of time. Telonium has a tool on our website that can be used to determine whether or not your internet is fast enough for VoIP.

Cloud Based

Used to describe a service which is hosted in the Internet, rather than you having a physical device.

QoS (Quality of Service)

The ability of a network to deliver traffic with minimum delay and maximum availability.

LNP (Local Number Portability)

Local Number Portability refers to the ability to transfer either an existing fixed-line or mobile telephone number assigned by a local exchange carrier and reassign it to another carrier.


VoIP Accessories:

ATA (Analog Telephone Adaptor)

This is a small adaptor that you plug into a normal analog phone to allow it to connect to a VoIP network and send calls over the Internet.

IP Phone

Sometimes called a VoIP phone, this is a phone which connects to a standard data network and is used to make telephone calls over the Internet. An IP Phone looks exactly like a regular telephone but instead of connecting to the phone line jack on the wall, it connects into a router.


An application or program which runs on a computer that allows you to make and receive calls, using a VoIP phone system or service. A softphone is designed to mimic the functions of a real telephone and often appears to look like a regular telephone on the screen. It is typically used with a headset to help improve the call quality. Skype is an example of a Softphone application.

I hope this list pushed you a little further towards understanding the world of VoIP. As always, if you have any questions or comments for me, I’d love to chat. You can contact me at <my first name>@telonium.com. Until next time.