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BT ISDN Switch Off

BT ISDN and PSDN Switch Off

The Great BT ISDN and PSDN Switch Off Misleading Sales Pitch

Unless you live under a rock, you would have heard BT is shutting down its ISDN and PSTN lines in 2025.  Now by now you will of had several emails and calls from companies offering to move you to their system before “The Big Shut Off”, Your own IT Company could have told you the same that now is the time to get rid of your dusty white ISDN lines and move to their super fast fibre connection (With a modest Setup fee and Management Fee).  They will go through all the benefits of using them instead of keeping with your current provider and that you don’t want to come in one day and it all be off.


What is an ISDN Connection ?

ISDN stands for “Integrated Services Digital Network.” It is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the traditional circuits of the public switched telephone network (PSTN).

There are two main types of ISDN connections:

1. **BRI (Basic Rate Interface):** This is typically used by smaller enterprises or residential users. BRI provides two 64 kbps B-channels (bearer channels) for data, voice, and other services, and one 16 kbps D-channel (delta channel) for control and signaling information. Thus, the total bandwidth for a BRI ISDN connection is 144 kbps.

2. **PRI (Primary Rate Interface):** This is more suitable for larger organizations. In North America and Japan, PRI provides twenty-three 64 kbps B-channels and one 64 kbps D-channel (for a total bandwidth of 1.536 Mbps). In Europe, Australia, and other parts of the world, PRI provides thirty 64 kbps B-channels and one 64 kbps D-channel, resulting in a total bandwidth of 2.048 Mbps.

ISDN was seen as a step up from the analog modem era and was particularly popular during the late 1980s and 1990s. It offered faster and more reliable connections compared to analog systems. However, with the advent and proliferation of broadband technologies such as DSL, cable, and fiber-optic connections, the significance and use of ISDN have greatly diminished in many parts of the world.


What is a PSTN Connection ?


PSTN stands for “Public Switched Telephone Network.” It refers to the traditional analog telephone system that has been in place internationally for over a century. The PSTN is also commonly referred to as the “plain old telephone service” (POTS). Here’s what you should know about it:

1. **Analog System:** Unlike more modern telecommunications networks that use digital technology, the core of the PSTN is based on analog technology, though many parts of the network have been digitized over time.

2. **Circuit-Switched Network:** In the PSTN, when a call is made, a circuit is established between the caller and the receiver, and this circuit remains dedicated to that call for its entire duration. This is different from packet-switched networks, like the internet, where data is broken up into packets and sent individually.

3. **Components:** The PSTN consists of various components, including telephone lines, fiber optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables.

4. **Signaling:** The PSTN uses dual-tone multi-frequency (DTMF) signaling, which is what you hear when you press buttons on a touch-tone telephone.

5. **Transition to Digital:** Over the years, much of the backbone infrastructure of the PSTN has transitioned to digital technology using T-carrier lines, SONET rings, and other digital technologies. Even with these upgrades, the “last mile” connection to most homes remained analog for a long time.

6. **Decline and Replacement:** With the rise of digital communication methods, including Voice over IP (VoIP) and mobile cellular systems, the traditional PSTN system has been on a decline. Many carriers are phasing out their analog infrastructure in favor of entirely digital or IP-based systems.

Despite its decline in the face of newer technologies, the PSTN has served as a reliable means of communication for many decades and laid the groundwork for today’s diverse range of communication methods.


Misleading Information

So the part that all these companies and your IT Company has neglected to tell you is that you can choose to do nothing and BT will do it all for you. You don’t need to change providers or spend money on new setups for broadband you can stay right where you are and wait for BT to contact you and upgrade your ISDN lines for FREE, Yes free no cost to yourselves. If you need to use a fax machine still you can plug it into the back of the replacement router you will get from BT.

I mean don’t take my word for it take a look at this page from BT: The UK’s PSTN network will switch off in 2025 | BT Business

This outlines what is really going to happen for the “Big Switch Off”


What I find more concerning is if your IT Support company has told you to move to their service but given you all the facts and just given you misleading information, where does this misleading information stop:


  • Your company is fully protected from Cyber Attacks.
  • Your data is all backed up.
  • Your Microsoft 365 is secure.
  • Your covered with your Cyber Insurance.
  • Your computers are secure.
  • You have all the protection you need.


If these are some of the things your IT Support company has said to you, then they could just be saying what they want you to hear. I would be concerned and start to ask questions with documented proof that you are covered in these areas. I know what your thinking, we just want your business and we are telling you this so you will move to ourselves!

Unfortunately we only take on a certain number of clients plus they have to fit within our values so not every company that comes to us gets to work with us under our MSP banner, however we offer consultancy work to any company. We offer several Consultancy services including:



Contact us if you want to discuss any aspects of your Business IT