The Ultimate Guide to ISDN End of Life

Businesses of all sizes still using traditional ISDN lines will need to modernise their communications systems to stay ahead of the coming changes. And, while 2025 seems a long way off, it’s never too early to check your current telephony contracts and start reaping the SIP rewards now by switching today.

Below we break down everything you need to know about the ISDN switch-off. 

ISDN switch-off: Everything you need to know


Making the switch to SIP

With the end of the traditional ISDN voice network looming, now is the time to make the switch to SIP. But what is ISDN and SIP, and why do you need to switch? We reveal all.

What is ISDN?

Introduced in the 1980s, Integrated Service Digital Network (ISDN) is the original high-speed internet service, deemed the successor to the dial-up internet service.

Like its predecessor, ISDN utilises a phone line. However, one fundamental difference is that it allowed businesses to separate their phone and internet operations, meaning both could be used at the same time.

While ISDN revolutionised the way businesses operated in the ’90s, the legacy systems – and their associated maintenance and running costs – are now considered widely out of date.

BT has therefore made the decision to phase out ISDN lines from next year, with a complete switch off date from 2025.

What does that mean for businesses still using ISDN? That's where SIP, or Session Initiation Protocol, comes in.

What is SIP?

A replacement to ISDN, SIP is a multimedia signalling standard, allowing you to communicate over IP connections rather than traditional phone lines. Then there’s a SIP trunk, which is the logical connection between your own telephone equipment and the service provider’s SIP equipment.

The end of ISDN means that it will be a necessity for businesses to switch to IP-based services, such as SIP, to avoid finding themselves without a phone system.

The advantages of SIP

There are several advantages that come with switching to SIP:

Cost savings: Compared to traditional ISDN solutions, SIP can save you up to 55% on your connection and rental costs and it can also result in significantly cheaper call charges compared to other services. Furthermore, pricing is generally more simple than traditional phone services, meaning SIP users tend to enjoy predictable monthly costs.

Unified Communications: Choose a SIP provider that offers Unified Communications as a Service (UCaaS), such as Node4, and you can have access to a broad range of integrated and certified communication tools. Your business can benefit from an IP-based communications suite that has the ability for everyone in your business to collaborate across many different channels seamlessly.

Valuable ROI: There are minimal upfront investment costs attached to opting for SIP. This, along with reduced telephony bills and increased call quality, means businesses are guaranteed an immediate ROI.

Mobility: SIP allows your business to redirect or route calls to alternative locations easily and quickly. This is useful for businesses who have a mobile or changing workforce, as well as during emergencies where the usual office locations are unavailable.

Scalability: With SIP, a business can scale the number of channels quickly and easily based on demand. During busy periods or seasonal peaks it is possible to temporarily increase the capacity. ISDN does not offer this flexibility as it is dependant on dedicated physical lines being installed into your premise.

Ready to give SIP a try? Here at Node4, we have total ownership, visibility and control of our SIP infrastructure. Therefore, we have complete confidence in delivering an outstanding service - every day, 365 days a year.

Contact us today for a free SIP trial and see for yourself the benefits of switching to SIP.