In 2015 BT announced its plan to migrate all users to IP networks and completely switch off ISDN and PSTN services by 2025.


Although BT did not specify the reasons behind cutting off ISDN, the announcement didn’t come as a surprise since ISDN had been facing a decline year on year with more businesses making use of modernised telephony solutions that provided greater flexibility and higher resiliency.



direct case study graphics-02The decline of ISDN


Even though ISDN has been diminishing for a while, there are still 3 million ISDN channels in the UK.  It might be true that BT does not have all of these channels on their network, yet a considerable number of customers are BT’s and they will be left with no choice but to migrate in the near future. That is why it’s important to future-proof your business and get familiar with SIP lines and VoIP to ensure you don’t get stuck with legacy technology.


At Wavenet we only work with the leading SIP providers in the UK - which we recommend to help you make the transition seamless.

Offering reliable voice connectivity between your PBX and their network. The benefits include increased flexibility, control, resiliency and reduced costs. 




direct case study graphics-03Number portability and flexibility

There is no geographical location requirements for numbers and SIP permits out-of-area numbers to be used since your phone number is attached to an IP address instead of a physical telephone line. So, for instance, a New York number may point to an office in London. Additionally, ISDN takes 6-8 weeks to implement, whereas SIP takes 24 hours to scale up or down.



direct case study graphics-07Cost-efficiency

The bottom line is important for every business and with SIP savings are substantial. With ISDN your voice and data are on different lines, whereas with SIP you can reduce costs by having them on the same one. Also, SIP trunks can greatly reduce call charges including international calls and free calls between multiple sites and offices on the same network.




direct case study graphics-06Scalability

SIP is deployed across your business’s existing WAN which means that you can add additional trunks in high demand and subtract them in low demand respectively in order to easily scale your telephony needs according to your business needs.



direct case study graphics-10Disaster Recovery

Incidents happen and at some point, your service could be interrupted by a network failure, a hardware problem, natural disaster or just bad weather. Luckily, one of the biggest benefits of SIP Trunks is the better reliability and much simpler disaster recovery when compared to legacy phone systems. If your business needs a zero-downtime environment, SIP trunks allow automatic failover solutions to be implemented so that your numbers will divert to other locations without loss in service.



For more information on the ISDN switch-off and what it means for you, download our free guide below.



Enquiry page Full-Fibre Future guide download





"Our mission is to be the most respected provider of data, voice and technology in the UK."

Our solutions have been evolved over the last two decades to allow us to innovate and provide our customers with the future-proof technology they need to stay ahead of their competition. Broken into four simple groups, our solutions cover all aspects of business communications and technology.
  • Unified Communications & Voice
  • Networking & Connectivity
  • Security & Compliance
  • IT & Technology Services


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Wavenet is a respected, multi-award-winning provider of telecoms and technology solutions to thousands of businesses and enterprises across the UK.


We are passionate about being at the forefront of disruptive technology providing our customers with the innovation and infrastructure to truly outperform their competitors.


We work with our customers to understand each business’s unique needs and challenges and build innovative solutions that are reliable, secure and future-proof.


Established in 2000, Wavenet provides a wide range of leading communications and technology solutions to medium and enterprise companies throughout the UK. We have grown to over 200 employees and more than 8,000 customers nationwide giving us the trust and experience required to make your Business Brilliant.



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