Phasing out of ISDN

Contact us

BT announced in 2015-16 that from 2020 you will no longer be able to purchase ISDN lines with a target date of 2025 for a switch off date.

Why are they doing it?

BT is giving a little tip of the hat in acknowledgement that communication has changed and that IP (Internet over Protocol) is the best next step for businesses to take; so they have decided not to invest any more time and money into a technology that won’t enhance the business world.

Also, let’s face it, it will be quite expensive to run all of the different networks. By converging all services to IP they only have to maintain one.

What happens if I have ISDN?

Well, you have time, so don’t panic. By announcing this 10 years in advance, BT has enabled you to have the time to plan in the investment of another option, the next best thing being IP. We advise that if your telephony contract is up for renewal in the next 2 years that you start exploring alternatives and put a plan in place by 2020.

It’s worth noting that for some businesses ISDN is still the best option and BT do recognise that so they won’t just switch it off without supplying a viable alternative in place, hence the decade long timeline.

What is my alternative?

You have two alternatives:

Hosted VoIP

Hosted VoIP is cloud-based and best suited to small-medium sized businesses who are looking for the functionality and scalability of a phone system with no extra maintenance charges. Each user has their own line and calls are routed through the internet. (View Benefits of hosted telephony here)


SIP and SIP trunks is an on-premise solution for a telephone system that will use virtual phone lines rather than physical wires. (View a detailed explanation of “What is SIP?” here.)

SIP is suited for larger businesses as it can prove to be more cost effective if there are a lot of users but there is a maintenance implication.

Compared to ISDN, both options are more flexible in terms of what telephone numbers you can have and the locations in which you can have them. They are quicker to install and offer a robust business continuity service that ensures your business never loses any calls.

Are you doing Research on the Phase-out of ISDN and Alternative Solutions?

We have a selection of resources available (for free) on the phase-out of ISDN.

View all Related Resources

Is it easy to migrate across to Hosted VoIP or SIP?

With the right provider – yes. You’ll be able to port and retain your numbers over. The whole migration (depending on some factors like the number of sites) it can take as little as 3 weeks.

What do I need to consider with the migration?

There are a few things you need to consider before you migrate; here is the general steps and some considerations you’ll need to make:

  1. Hosted VoIP or SIP?
  2. Planning number of virtual lines required.
  3. Checking the internet connection is able to handle this system.
  4. Checking that your current handsets are compatible with VoIP or SIP.
  5. Setting up phones (physical handsets or softphones.)
  6. Porting over the phone numbers.
  7. Testing.
  8. Securing the system – ensuring there is a disaster recovery solution in place.

Okay, I need to start talking to someone about this!

We’d be happy to give you some advice as to when you need to make the switch and any more considerations to make; as always, our advice is free.

Share this post...

For free advice speak to Robert Bright or
Shiv Passap on 0330 222 0330

Contact us