The BIG ISDN Shutdown in perspective


From January 2020, you were no longer able to purchase additional ISDN2e or ISDN30e lines. Although, this doesn’t mean you cannot use your existing lines. However, it does mean you can no longer add new ISDN lines, should you have ISDN2 or ISDN30.

he cost of preserving these lines far outweighs the benefits, with many alternatives being better cost-effective and faster. OFCOM published an extensive article where they stated, “the key benefit of IP-based products including SIP Trunks which has been sold to customers is lower cost vs ISDN30.

In 2025, these ISDN lines will no longer be functioning. With this date fast approaching, companies will need to implement new solutions sooner rather than later. Know the facts so you are well versed on the subject when any telecoms provider approaches you. Make well-informed decisions.


The most important thing to know: is this even a problem for your company? Substitutes to ISDN have been in use for a while, so your business may be already using one. This could be in the shape of SIP connectivity to replace your ISDN or a  Fully Hosted cloud-based solution that could have replaced your ISDN and your telephone system altogether.

If you don’t know what kind of lines you have, we check your bill to confirm.


If this stoppage affects you, do not panic. You still have time to implement a new working strategy, finding a new alternative service that suits your company’s needs, budget and aspirations.

Alternatives to ISDN lines are far quicker IP based connections like SIP or cloud-based systems. One thing to be aware of is that these systems rely upon good data connectivity to provide superior service. Precisely, they are reliant upon a good quality upload speed. If you are anxious about your upload speed, or the cost of implementing an alternative to ISDN, do not worry. A government scheme to improve businesses’ connectivity can offer you up to £2500 to subsidise these install costs. This can help ensure that your move from ISDN to IP based connections does not create a financial burden.

The benefits of a 1-Voice SIP or 1-Voice Fully Hosted cloud-based system are clear. It is far easier and faster to divert each DDI or direct dial-in numbers. Should there be a dilemma and the service go down, a SIP divert can occur in a minute or two, diverting all DDI’s, whereas ISDN divert can’t divert individual DDIs, and it can take up to 24 hours. SIP can also offer you free minutes and DDI rental free. 


When you enquire about alternatives to ISDN, there are some crucial questions you should ask. Firstly, who the carrier or supplier is and how many colocations they have. Colocation is the use of an individual data centre as a shared facility. In terms of colocations, you should aim for at least 3 or 4 locations. But the provider must be ‘hot resilient’. This means that should a data centre go down; the calls are automatically transferred to the following data centre – making it a flawless change. Some services may offer multiple colocations, but they must be indifferent colocation data centres, making them more ‘resilient’ should there ever be an issue. Also, check what they offer for call fraud protection. 1-Voice uses the Best of Breed Cisco Broadsoft platform as the core of it’s offering, thus guaranteeing best of breed solution and resilience.


We would recommend initially Switching from ISDN if you are planning to:

  • Upgrade your telephone system (you can keep your investment if this is IP Compatible and we may be able to make it work in a Hybrid mode)
  • Move office location
  • Expand your current telephone system

These are ideal scenarios for considering a change. The sooner you consider switching from ISDN, the better, and nothing is stopping you from switching today. Contact us today if you need support.

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