Posted on 29/11/18

In 2025, BT is due to switch off ISDN and PSTN services. But what are they and how will the switch off impact your business?

Over the following article we’ll take a look at ISDN, PSTN, why the switch off is occurring, what you can do within your organisation to ensure you’re ready for the change and what Challenger can do to assist you in the process.

Public Switched Telephone Network (PSTN)

The public switched telephone network (PSTN) is the term used to refer to all the world’s circuit-switched phone networks which are operated by a range of suppliers (generally national, regional or local telephone companies). These systems send voice data through copper wires owned by the phone providers via analogue signals.

Integrated Digital Services Network (ISDN)
Essentially, ISDN is a group of communication standards which allow the simultaneous transmission of video, voice, data and other network services via the circuits found in the public switched telephone network (PSTN). Simply put, your standard phone line is utilised to send both voice and data over the same line. ISDN was introduced to the UK by BT in 1986 but since then connectivity technology has advanced considerably and ISDN has started to be outmoded.

Why the Switch Off?
In recent years there’s been massive investment and roll out nationally in super-fast fibre broadband as well a broad variety of new Ethernet alternatives which provide improved service over ISDN and PSTN. BT hasn’t actually installed any new ISDN lines within central London since 2014 which is an indication of just how many organisations have already moved away from the technology.

However, there are still many companies and individuals (roughly three million) who use ISDN. It’s for that reason that BT has given such a long notice period for the switch off.

What comes after ISDN?
Recent investment in the communications networks within the UK has made fibre-broadband services widely available and affordable to small businesses. What this means is that IP based alternatives (VoIP/SIP) are the most viable alternatives for your business post ISDN.


Voice over Internet Protocol (VoIP)
VoIP is already in use by many organisations. It’s a cloud based phone system, which means all your incoming or outgoing calls are sent over the internet.
VoIP has a broad range of additional features over more traditional ISDN systems such as:

  • Call Recording
  • Able to receive voicemails over email
  • Call Queuing
  • Accessible via multiple devices (mobile, desktop, tablet etc.)

Challenger are expert VoIP providers, with years of experiences in integrating the technology into effective use within an organisation. Please visit here (link to VoIP page on site if there is one) or call us today to find out how you could use VoIP within your business.

Session Initiation Protocol (SIP)
Although SIP systems once suffered from reliability problems, since the aforementioned investment in communications these issues have been fixed. SIP is a phone line carried directly over your fibre broadband connection, eliminating the requirement for an ISDN phone line in its entirety.
At Challenger we’ve been providing SIP lines for years. We’ve helped many organisations make the switch from ISDN to SIP services. If this is something you’d be interested in discussing with us, get in contact today 01244 837837!

Why should you Switch early?
We’ve a while to go until 2025 but that doesn’t mean you should wait until last minute to switch your service away from ISDN. There are many advantages to switching to either VoIP or SIP right now and at Challenger we’re ready and waiting to help you through that process.
So, what are the advantages of switching to SIP or VoIP?

  • Massive Savings – As calls will now route through the internet, the days of paying line rental are in the past! You’re likely to see somewhere in the region of a 75% reduction in costs overall.
  • Supreme Flexibility – Plug in and connect anywhere in the UK. Move offices without as much hassle or integrate non-office based staff into the system without unnecessary issues or effort.
  • Quicker Install – You won’t need to wait for an engineer to come out and install new lines or anything like that. You’ll get going with VoIP or SIP much faster for that reason.
  • Resilience – You can have more than one fibre line installed to allow for a backup should the line ever be damaged or fail. This means you can continue business uninterrupted.
  • Features, features, features – As we touched on earlier in this article, IP solutions like VoIP and SIP over a broad range of features which simply were not available on ISDN networks. You’ll have better control and integration as well as in-built analytics systems which will give you a better view of how the systems are working for you.

At Challenger, we’re ready and waiting to help your and your company make the switch away from ISDN. We have almost two decades of experience in communications technology and we’re a direct partner to O2.
What that means is, we can provide you with the personal service of a smaller organisation with all the logistical benefits of working with a large one.’

Jeff Eamens, Sales Director

If any of the above sounds of interest to your business or if you’d just like more information on how Challenger can help you switch away from ISDN today, get in contact!

Our expert team is waiting to help. 

Tel: 0800 269 546 Email: info@cmc.uk.net

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