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The ISDN phase-out

The Integrated Services Digital Network (ISDN) began its phasing out process earlier this year and is expected to be shut down permanently in 2025. We explore why this transition is taking place, the potential benefits for business leaders and the importance of immediate and future preparation for the change.

2 December 2020

A brief history of ISDN

An ISDN system is a circuit-switched telephone network originally designed to migrate obsolete landline technology to a digital format. It can transmit both data and voice over a single digital link.

ISDN was first formalised as a national standard in 1988. While it did enjoy initial success, technological advances meant that its embrace by consumers was lukewarm at best. Primarily this is due to a combination of logistical factors such as cost to install, maintain or remove, capacity, and the space it occupied on business premises.

These physical challenges also limited business expansion, relocation, and adaptation to changing markets. Despite robust support from suppliers and regular updates, alternate technologies like DSL (Digital Subscriber Line) and VoIP (Voiceover Internet Protocol) have long-since surpassed ISDN in several key categories.

As a result, BT Openreach announced in 2015 that it would begin phasing out ISDN this year. Plans include ceasing purchasing in 2020 and conducting a system-wide shutdown at the end of 2025.

Since then, BT Openreach have actually extended the purchasing window up until 2023. However, the success of competing systems means that this has merely postponed the inevitable.

During lockdown, many businesses that hadn’t relied on VoIP previously experienced the necessity of systems like Skype and Zoom, without which crucial elements of remote work would not have been possible. Has lockdown accelerated the switch given how it has exposed the limitations of ISDN compared to its counterparts?

While the 2025 deadline might still be subject to change, market momentum points towards the switch happening and your business will want to be ready when it does.

What do businesses need to do?

Review your current ISDN contract and set-up.

The first step is to avoid renewal of any existing ISDN contracts you have. Now is the time to review the terms of these contracts. Make sure you are not scheduled to renew automatically.

Alongside auto-renewal schemes, there may be obligations on your contract that prevent switching before its term is up. Either way, take some time now to calculate your earliest switch date and start building a timeline for transition around that.

Next, consider what your current and future needs are likely to be, and what scale and type of set-up is required to serve them. Are you lacking capacity or bandwidth for work from home functions? Do you plan to move or restructure business real estate in the near future?

It’s important to understand the scope for changing needs because, although newer technology will have innate flexibility, you don’t want to commit time and resources to a system that cannot fulfil them.

Shop around

We’ve spoken a lot about VoIP and the technology has certainly proven its worth in the last six months. However, once you have reviewed your current systems, you will have a clearer idea of your budget and needs. VoIP is not the only option available after ISDN.

SIP (Session Initiation Protocol) Trunks differ from VoIP in that they still use hard-line connections. It’s an internet version of technology similar to ISDN, however they differ in two crucial aspects: they are much cheaper, and much easier to scale. SIP best suits premises already possessing a phone system on-site.

While SIP may require initial maintenance to ensure compatibility, it offers high call quality and lower call costs. Lines are much easier to add and remove according to changing needs, compared with ISDN. However, this does impose maintenance costs.

VoIP, on the other hand, requires no on-site hardware whatsoever. That is because it can piggyback off your existing internet connection and is best suited to sites that have no pre-existing phone system.

Seek advice

Since telecommunications contracts often span several years, the market is subject to significant change in that time. Unless your business already specialises in telecoms, it might be worth getting some outside expertise to guide your migration. Doing so means avoiding complex procurement proceedings that could be outsourced to a specialist who can navigate questions of capacity, cost and the logistics of any installations that might be necessary.

The right guidance can also investigate how to mitigate costs through external
support like the Government Gigabit Broadband Voucher Scheme.

How Smith Bellerby can help

At Smith Bellerby, we collaborate with our clients to create a bespoke service package. We are experts in all aspects of utility and telecommunications management. We will interact directly with your suppliers and provide guidance on alternative contract and procurement options to ensure you are getting the best deal possible. If you would like to discuss your future telecommunications needs or devise a plan for the ISDN switchover, please get in touch.

Evelyn Chapman Author
Evelyn Chapman
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