30th October 2019

ISDN countdown to the switch off


As we edge closer to 2020, businesses will need to start exploring alternative telephony solutions to replace ISDN lines before the official switch off in 2025.

Technology has vastly improved, gone are the days of copper wiring that provided the opportunity to transmit both voice and data over the same line, simultaneously. Enter internet calling....But first, let’s explain exactly what ISDN is and why it’s important that you save a date in your diary.

Sian Webster Head of Marketing

What is ISDN?

Integrated Service Digital Network – more commonly known as ISDN was launched by BT in the 80’s as a means to update archaic landline technology to digital. At the time, business owners couldn’t believe their luck – getting the chance to use a system that supported both analogue phone lines and early video-conferencing – all whilst listening to Chris de Burgh, The Lady in Red. Win-Win.

Let’s not forget, this was a time where the fastest internet access available was 128 kbps – they were really in their element.

With faster speeds and better connections that came with ISDN, business owners could send data with little to no distortion, something that simply wasn’t possible with previous antiquated systems.

Fast forward to now – ISDN is basically an outdated legacy system that’s often used as a backup phone system when the main line fails.

Why is ISDN getting “switched off”?

Long story short – ISDN takes up space, a lot of it. It’s also costly to maintain and it’s difficult to fix if things go wrong.

Most importantly, BT understand that the way we communicate has changed and VOIP (Voice Over Internet Protocol) is the best next step for businesses to take… plus let’s face it, ISDN is time consuming and not to mention expensive to run – by converging all services, they only have to maintain one.  It’s a no-brainer.

What does the ISDN switch off mean for your business?

Over the next 5 years, ISDN will be phased out completely, so if you’re coming up to renewal, now is a good time to start thinking about the possible alternatives….

SIP Trunking

If you have a modern on-premises phone system, SIP Trunking is the best alternative solution. Session Internet Protocol (SIP) uses virtual phone lines as opposed to physical lines like ISDN. SIP trunks offer a more flexible and lower cost alternative to traditional ISDN for inbound and outbound voice calls.

SIP trunking connects your phone system (PBX) to your provider via broadband, ethernet or private circuits. When combined with Vivio Broadband or Lease Line connectivity we can deliver a complete end-to-end service to guarantee availability, voice channels and quality of service.

Reasons you should consider it…

  • Make huge savings on call costs
  • Adding lines is really easy, helping you meet business demands
  • It’s super reliable, unlike ISDN
  • If your existing phone system is compatible with SIP, you may not have to replace it

Hosted Telephony

Hosted IP phone systems use your internet lines on a virtual phone system – a great option for companies that don’t want to commit or retain an on-premises phone system.

It’s essentially a telephone system that resides in the cloud rather than in your office. Users access the system through a standard IP handset or a softphone – a screen-based virtual phone with headset. Calls are made and received over a broadband connection and from there they are routed to PSTN fixed and mobile devices.

Reasons you should consider it…

  • A scalable, flexible option with no hidden costs
  • Free calls to UK landline and mobile (01/02/03/07)
  • Future-proof technology with no expensive upgrades
  • No need to worry about unexpected events, such as snow days
  • Seamless integration of multiple locations with free calls between sites


The clock is ticking! If you’re ready to start the conversation about how to migrate across to SIP or hosted telephony, speak to our dedicated team today on 01244 305130 or contact hello@vivio.co.uk


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