May 25th 2017


Ever wondered what an ISDN line is, or what PBX means? Well, I did and researching for the answers was littered with pestering technical talk that I didn’t understand. I wasn’t getting a clear answer. On this post, you will find clear-cut answers to phone system jargon. When purchasing a phone system you need to know exactly what you’re buying and learning the basics are best.


VoIP stands for ‘Voice over Internet Protocol’ which is technology which is set out so that the internet can be used to transmit real-time voice communication for telephone calls. Basically, it allows you to make phone calls using the Internet rather than traditional phone lines.

VoIP is more common than you think. Skype, Viber, Google Hangouts. These all use VoIP technology to work. As a relatively new technology, VoIP has been pretty successful and lots of businesses use VoIP on an everyday basis. Most calls made using VoIP are cheap which is why businesses are attracted to it. There are VoIP Phone Systems built for business, focusing on improving productivity and giving you a better level of communications, whilst also saving you money.


PBX stands for Private Branch Exchange. It’s a private telephone network used within a business, such as for workers in the same building to communicate. Calls made from worker to worker using a PBX are free and make in-house communication convenient. Modern PBX phone systems now use IP to work, making them the perfect method of enterprise communication, more on IP later.

Each worker has a unique 3 to 4 digit long phone number so it’s easy to remember your work buddies number to talk about ‘work’. Too much shouting in the office? A PBX is your solution…or group anger management.


ISDN (Integrated Services Digital Network) is technology that allows the transmission of digital data (voice communications aka phone calls) through traditional phone lines. You need to have a phone line to use an ISDN Phone System. ISDN phone lines were used commonly before IP lines came in. They were first put into place in 1986. Yep, by technology standards, they are really old but they have aged quite well.

However, BT’s ISDN lines are going to be shut down by 2025 and all users will be forced to SIP service instead. It’s best to switch now to avoid the mayhem that will befall during the purge of ISDN (in the UK).


SIP, Standing for Session Initiation Protocol, establishes, modifies and terminates voice, video, messages and other forms of communication, such as VoIP, from one IP network to another. It basically allows you to make voice, video and other forms of media calls from one computer to the next. It is quite a popular as you are able to transmit more than just voice. SIP lines are cheap too and can save you 30% to 60% on your monthly line rental if you currently use ISDN or analogue lines. Find out how you can switch to SIP today.


Analogue lines, also known as Plain Old Telephone Service (POTS, not POTUS) allows phone calls to be made through old school copper wires. These copper wires will need to be hooked up from the place of use, such as your office, all the way to your local phone company’s office. Using Analogue lines now can be expensive. So, if you wanted to have 100 telephone lines you would need to install 100 pair (200) copper wires. That’s right, 1 line per user.

They are EVEN older than ISDN (standard service in 1876), older than 150 years and it still amazes me how many businesses use them for their main communications. Analogue lines support fax machines and can even be used during a power cut which is neat. But, because it’s an old service, phones that use them will not be feature packed. There’s no video conferencing, visual voicemails or the other fancy stuff you can do with modern VoIP systems.


IP stands for Internet Protocol which is a method of transferring data from one computer to another, through the use of the internet. Now you may be asking, isn’t that what VoIP does?

Well, VoIP specifically means the transmission of VOICE over Internet Protocol, over the Internet. IP is the main concept of making phone systems ‘digital’ and allowing the use of the internet to send data. Think of it as a spider-gram. IP is the centre and branches out to VoIP, which then branches to SIP.

When talking about IP, calls will usually be made through the public internet. However, an IP-PBX will use your own private data network, your intranet (your own internet dedicated for your own organisational use). Using your private internet, you get more control and a better quality of communication than using the public internet.


Hosted means to store something so that it can be accessed anywhere through the internet. A Hosted Phone System, also called a ‘Cloud-Based’ Phone System is a phone system which can be accessed in any location using the internet. You will use your Desktop to connect to the Phone System. The actual system will be stored in a safe place by the provider.

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