history of telecoms

Don’t Believe the Lies

There are many telecoms companies who will have you believe that BT are turning off their ISDN service and that means BT are turning off all phone numbers that run over their copper imminently.


BT Openreach’s Public Switched Telephone Network (PTSN) will reach end of life by 2025 and that is what supports products such as ISDN2 and ISDN30. They are currently planning to phase out their ISDN service from 2025. There is no rush for you to make the change, from ISDN. BT is not going to cut you off. However, there are 16 million lines that need to move by that point.

There are, however, a range a reasons why migrating from ISDN solutions to others would be beneficial for your business. Let’s look at them now.

1. Flexibility

When your phone calls go over ISDN, they can only go to one location; where your phone system is. With a VoIP or SIP solution, your calls go to wherever you are.

  • To another office
  • To your mobile
  • To your laptop
  • To your home – if you really want them to

If your teams need to be highly mobile, but also need to be contactable, an ISDN solution will not meet your needs. Imagine how much more productive your teams can be if they can communicate quickly and easily from wherever they are.

2. Cost management

ISDN contracts are based on a fixed number of lines for a fixed period of time. If your business is growing, this is less of an issue. You may get to the point where some calls cannot get through (you don’t need an ISDN line per person, it’s per concurrent call per line that’s important). You simply add more lines at that point. However, if the number of people working from a specific location gets smaller, you will be wasting more and more money on lines you don’t need. That can be renegotiated at the end of the contract, but not at any point before that.

3. Improved business continuity

If something happens that means you cannot use your office, you want to be able to work productively from another location. This may be a serviced office (if the closure is expected to be for some time), from client locations, from home or even coffee shops (for an hour or two…). Without a solution that allows you to divert calls accordingly, your clients, prospects and suppliers will be calling your office and becoming increasingly frustrated because they cannot reach you.

4. Scalability

Is your business trading pattern the same throughout the year? Or does it have peaks and troughs that mean staff numbers expand and contract? SIP and VoIP solutions can be adjusted on a monthly basis, adapting precisely to your business needs.

5. Opening/closing new locations

If you’re opening a new location, you will need to plan ahead if you have a ISDN solution. Lead times are at least 20 working days, whereas an internet-based solution can be turned on almost instantly. If you then need to close that location, you are still paying for ISDN lines because of the contract.


If you do get companies telling you that BT are turning off their ISDN service, simply tell them you know they are lying. Whilst they are trying to get you to think about alternative solutions, that come with a range of benefits, a lie is never the best way to start a relationship.

If you are getting calls from companies lying to you in this way, and want a more accurate conversation, give us a call: 020 8912 0845