The Phone System Jargon Survival Guide

Quick Quote

You can get a quote for telephone systems by answering the four simple questions

Quick Quote

Have you ever been in a discussion with someone from Telecoms and found the person you are listening too seems to be talking an alien language?

Well you are not alone, most people don’t buy telephone systems very often and all the acronyms and jargon we use in our industry can be a put off in itself so we figured we would put together this useful quick reference blog for anyone wanting to understand the basic most used jargon as a quick survival guide reference for anyone buying a new telephone system.

We hope this is useful to you and would love to hear from you if you have any questions or want budget price for a new telephone system for your organisation.

Trunks or Lines… External phone lines coming into your business phone system. You need to make sure you always have enough.

ISDN2 or ISDN30… A type of external phone line most commonly used, Integrated Services Digital Network is what ISDN stands for, digital lines provide enhanced functionality.

PSTN… This is a type of external telephone line also known as an analogue line, generally used for fax, broadband services or alarms. PSTN stands for Public Switched Telephone Network.

SIP… This stands for Session Initiation Protocol and is a common standard used for the delivery of telephone line services using the Internet as opposed the traditional telephone network.

Extensions… Internal telephone within your own business.  Extensions are not only useful for internal communications but used to answer and transfer calls to, extensions can also be used for fax machines and/or modems.

Ports… Usually refers to the number of connections that the phone system is capable of having. This combines lines and extensions.

KSU or CO… The cabinet, also known as the Key System Unit or the Central Office is the main box that contains internal and external routing settings.

ACD… Automatic Call Distribution a common feature that handles large numbers of incoming calls via scripts or pre-programmed sequences that distribute calls within the network.

POT or POTS… Acronym for Plain Old Telephone System, the type of network that uses landline connections to transmit sound information.

PSTN… Public Switched Telephone Network.

Key Systems… Known as key telephone systems, are the entry-level choice for small business phone systems.  Each phone has buttons corresponding to the number of phone lines available.

VOIP… Stands for Voice Over Internet Protocol, a common and useful phone system type that uses the Internet to transmit sound (your conversations or calls). VoIP Phone Systems use and benefit from traditional office phones, using an internet router and lowering costs when compared to land line calls.

PBX… Also Private Branch Exchange are customizable phone systems that differ from “key systems” in that users of key systems manually select their own outgoing lines, while the PBX selects the outgoing line automatically.

PABX : Private automatic branch exchange
EPABX : Electronic private automatic branch exchange
Hosted PBX :Can work with both with Public Switched Telephone Network and/or the internet. In addition to all office phone system features it allows a single number to be presented for your business, regardless of its location even if workers are connected from home with domestic phones.

To find out more about telephone systems and how they could work for you, please give us a call on 0800 50 533 50 and one of our team will be happy to help, or view more information on our main website.

Like This?
You may also like:


Business Services

moving office

I am moving office

Moving office phone systems can be stressful, we can help with your office relocation.

Setting Up New Office

I am setting up a new office

Find the right location, design the workplace, negotiate a lease or decide on buy.

Review telephone services

Phone service review

Detailed cost service review of all your IT and telecoms costs and services.

Managed Voice and Data

Managed phones and internet connections

Specialised voice and data services for corporate customers throughout the UK.

Latest Tweets

See our latest tweets from the Tech IP Twitter feed. Follow us on all our social media channels to stay up to date with the latest business telephone technologies. Watch our Youtube channel for informative videos on our cloud phone systems, Unify communication solutions, and more.

Our Partners

Below are some of the companies that are partners with Tech IP. Please click on the logo for more information on each of our partners.

Communication Products

Apple Mac - Internet Services

Internet Services

Secure, robust and reliable internet connectivity from a wide range of suppliers covering all types of connections.

cloud voip phone services

Cloud Phones

Cloud telephone solutions designed for your business cloud phone telephony is the future for high performance.

Network cabling

Network Cabling

We provide Cat5e, Cat6a and fibre network cabling systems including everything you need for a secure functional comms room.

Samsung Galaxy phone line up


We can review your mobile phone contracts, considering all networks to find the right deal for your business.

Video Conferencing

Video Conferencing

A complete range of advanced video conferencing from world-class manufacturers.

Business Phone Lines and Calls

Business Phone Lines & Calls

We can review your current business phone lines and call packages to find the right services to suit your business needs.