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What actions your business may need to take before the big ISDN 2025 switch off.

If your business’ phone calls are handled by a private automatic branch exchange (PABX) system it will almost certainly be connected to the telephone network using an ISDN line but with the ISDN 2025 approaching, you need to start thinking about what to do.

But by 2025, BT is planning to switch off both the ISDN network and the outdated public switched telephone network (PSTN) as it moves to an entirely IP-based model of voice communication. So, what does this change mean for your business and do you need to take any action before the ISDN switch-off takes place?

What is ISDN?

Let’s first differentiate between PSTN and ISDN. The PSTN transmits voice calls using copper cables and the fundamental basics of the system haven’t changed for many years. ISDN however, introduced in the late 1980s, allows both voice and data to be combined on one digital line.

These days, ISDN’s primary use is to connect PABX systems. This is because the line can be subdivided into channels, each one effectively acting as a separate telephone line allowing multiple calls to be made. The problem with ISDN is that it is often expensive and if you need to extend your call capacity it can often mean adding additional lines that incur additional costs.

But despite being a well-established and reliable service, the widespread rollout of fibre optic services means many of ISDN’s advantages have now started to disappear. With retirement on the horizon, let’s look at what the future holds.

Voice over Internet Protocol (VoIP)

Thanks to the rise of fast, fibre internet connections, it has become possible to make phone calls over the internet using Voice over Internet Protocol (VoIP) technology. This is a cheaper and more flexible option which has largely contributed to the ISDN switch-off decision.

A VoIP solution can mitigate the need for expensive, dedicated lines for your business’ voice traffic and with many businesses having already made the switch, this has led to an overall fall in demand for more traditional services.

It also allows for a more versatile system. Users can log into and use VoIP services wherever they have an internet connection which is great for businesses that employ home or field-based workers or those based in branch offices, allowing them to access the same business telephone system.

VoIP also integrates with mobiles and with computer systems in a unified communications (UC) strategy that allows for solutions such as hot-desking to operate successfully. Scalability is easier too, as when you want to add more capacity you no longer need to install an extra line to do so.

And finally, VoIP is a more cost-effective solution; not only do you mitigate the need for expensive line rental but overall call costs are lower too.

What next?

If you are planning to move to IP then there are a number of things you need to consider. Firstly, you will need to ascertain whether your existing PABX system is compatible with IP. Many newer systems will be, but if you have older kit you’re going to have to replace it.

There’s an opportunity to make a switch to a cloud-based system here too which can save on the costs of an in-house system as well as giving you a range of extra features. You also need to look at whether your existing internet connection is up to the job. It’s recommended that even for small offices you need a fibre connection as a minimum in order for VoIP to work successfully. Larger offices will obviously need more bandwidth and this is where broadband can cause bottlenecks.

Broadband is asymmetrical which means there is less bandwidth for uploading data than there is for downloading. It also suffers from what is called contention, because the connection is shared with other users once it leaves your premises, meaning you get significantly less bandwidth at peak times. You may have noticed similar instances with your home broadband where it seems slower in the evenings at times where more users will be streaming TV programmes or films.

In preparation for the ISDN switch off, therefore, you may want to consider upgrading your connectivity to an Ethernet-based solution. This overcomes the drawbacks of broadband because not only is it a fully symmetrical connection – the same speed in both directions – but there is also zero contention meaning you have all of the bandwidth solely for your use.

Choosing a provider

Switching to VoIP provides an ideal opportunity to switch to another service provider. Many businesses do this in order to save money, but cost shouldn’t be the only consideration.

Look carefully at each provider and the levels of service on offer. Remember that the explosion in VoIP services in recent years has brought about a proliferation of suppliers, but make sure the supplier can cater for all of your business’ needs as well as those of your telephony systems.

You will also need to keep your existing phone numbers. This is a process known as ‘porting’. Simply put, phone numbers are provided to suppliers in batches and there’s a lead time – usually of about 30 days – to get numbers transferred. You also need all of the billing information and paperwork related to each line in order for the process to run smoothly.

A good VoIP supplier will be able to take care of the porting process for you and should be able to manage the entire process of switching from ISDN to IP, so that you and your business don’t experience any loss in service during the changeover.

Despite ISDN’s switch-off being set for 2025, UK businesses can expect to see action starting to occur before then. From 2023, businesses will no longer be able to buy new systems or maintain existing systems that use PSTN or ISDN technology. So if you’re looking for a new system now, it makes perfect sense to opt for an IP-based option sooner rather than later.

BT will have migrated everyone to an IP-based system by 2025 and while you could just wait, switching earlier can give you a competitive advantage much sooner, especially if you move to a different supplier at the same time.