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VoIP Glossary – Top Terms to know


There is a fair amount of technical jargon used in the world of VoIP Communications and as a VoIP reseller you are going to want to know what it all means. So, we have put together this handy VoIP glossary for you. Please let us know if there are any other VoIP glossary terms you’d like to know in plain English.


VoIP Glossary Terms


We thought we would start with the most obvious one first!

VoIP is short for voice over internet protocol and the simplest way to describe this is it is voice and data communications transmitted through the internet instead of traditional analogue phone lines.


This is an Analog Telephone adapter. Basically, this is a way of converting analogue voice calls into digital data which can be sent through the Internet.


This is how much data can be transferred between two points. If there is not enough bandwidth it is like a country road with a 30mph limit.

Bandwidth is measured in bits per second (kbps)


Short for Bring Your Own Device, this is where employers allow their staff to use their own devices for work, mobiles, laptops and tablets.

The Cloud

Effectively this is off-site and virtual storage. Many VoIP systems are cloud-based, which means less money and space taken up with big switchboards and servers.


Codec is short for code/decode. It’s software for taking voice or video, converting it into data which can then be sent through the internet and decoded at the other end.

Calls are coded for two main reasons, security and the fact that it would take a lot longer to send if they weren’t coded/decoded.


Not as exciting as it sounds, Dynamic Host Control Protocol is the method used by IT Departments to issue and manage IP addresses (more on this below) to any devices connected to their network.

IP Address And Protocol

These two sometimes get mixed up, IP stands for Internet Protocol which is how packets of data are moved around on the internet.

IP Address is the unique set of numbers given to a device that is connected to the internet.

If you go to you will see that your device has a set of numbers.

You will also see the IP address tells you your location and your internet provider.


This is probably quite self-explanatory too, but a jitter is a small interruption in call transmission, usually caused by a network drop or spike.


KBPS is kilobits per second, and it is the speed which is used to measure the speed of data.


Slightly longer than a jitter, you will hear about lag or lagging on video or voice calls and it means it is taking longer than it should for the data to transfer.

This is often most noticeable if the sound on a video call is out of sync with the picture.

It is usually caused by network or bandwidth issues.


You will often hear about network latency; this is how IT departments will measure the speed of data transference by sending a packet of data to see how long it takes to get there and back.

So, latency is used to describe any delay and anything that causes the delay is a lag.


Packets is the term used to describe the data in a VoIP transmission, it packages up the relevant information, including the call, the details of who is sending it and the device details.

Which leads us neatly onto…

Packet Loss

If a network is unable to deliver and open packets, then this is called packet loss. This is usually caused by latency or if a network is overloaded with data and can’t handle the packets.

Packet Switching

Packet switching is a way of dealing with packet loss. The packet is split into different sections, sent on different routes and then packaged up again at the other side.


PBX is a Private Branch Exchange and is simply a private telephone exchange switchboard.

It connects internal telephone numbers and extensions together and to the outside telephone network (PTSN).


Session Initiation Protocol, or SIP for short, is the communications standard for starting, managing and ending any communications using voice, video, VR and gaming.

This is the standard way for any VoIP telephones to operate.


PTSN stands for Public Switched Telephone Service and is the name of the traditional, global, telephone network structure.

Get In Touch

We hope that our VoIP glossary will help you when you start out as a VoIP Reseller, not only for you and your customers but when you are communicating with IT Depts.

If there are any other technical terms you would like us to add to our VoIP glossary, or if you would like to find out more about our VoIP systems or the VIP VoIP reseller propositions, then please do not hesitate to get in touch.

Our team of experts will be more than happy to have a chat with you.

You can call us on 03300 881182, email or use our online contact form here.