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Are you ready for the PSTN and ISDN switch off?

Confused? Let us help…

So, PSTN, also known as Public Switched Telephone Network, is the traditional bog-standard telephone line that we’ve been using since the 1800’s. Remember that guy, Alexander Graham Bell? No? Me either. Well anyway, we’ve been using his style of work pretty much ever since.

In a world of forever evolving technology, why wouldn’t you want to upgrade. I mean, look how far we’ve come since the first mobile, wouldn’t you want that for your business landline too?

PSTN is made up of telephone lines, fibre optic cables, switching centres, cellular networks, satellite and cable systems. The way in which PSTN works is there are copper cables under the ground across the world and centralized switches to enable communication between two points on a network.

Stay with me.

The copper network cables have switches on that work as nodes (these are connection points that create, store and send data across network routes). A call can be placed after being passed through various switches from different networks and delivering a voice signal. These switches are the reason we have area codes/country codes.

There is also such thing as ISDN. This stands for Integrated Services Digital Network. This is the original high-speed internet service introduced in the 1980’s. This service allows multiple lines to work simultaneously whilst only using one copper pair that we mentioned earlier. ISDN also allows the use of DDIs (Direct Dial inbound) so that individuals can have personal telephone numbers alongside the main number. In short this means; a single line that can deliver multiple telephone numbers and channels digitally, all under one roof.

Still with me?

Great! Now we have that out of the way, I can explain what this means for you and your business.

By 2025, BT will be switching off the PSTN and ISDN lines. This means that before that cut off point you will need to switch over to an IP line. These will either be Voice Over Internet Protocol (VoIP) or Session Initiation Protocol (SIP).

It’s a lot less complicated than it sounds, we promise!

Instead of having multiple lines, you will only need one fast data connection which will also carry your voice calling. In simpler terms, your calls will now be through your internet.

Although it sounds like a lot of hassle, it’s really not, and there are huge benefits to your business for using a cloud-based system.


More Cost Effective – Up to 78% cost reduction. This is due to cheaper calls as they’re through the internet and not having to pay out for expensive line rentals.

Flexibility –In the new age of flexible working you have the ability to physically move your phone wherever you go, providing you have a broadband connection.

Set Up & Maintenance – Due to having less equipment on site, there is less to install and less to maintain.

Still confused? Give us a call on 03333 212 707.

We’d love to answer any questions you may have regarding the switch, your current system or moving providers in this time.

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