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Guest blog post from one of ITP's Esteemed Fellows

Since around 2008, where ever possible, transmitting voice services over an Internet connection* (rather than an analogue / PSTN or digital / ISDN phone line) has been in testing within the industry with clients and customers who were asked to be early adopters of this technology.  

There have been rumblings within the industry since 2008, that Openreach, the division of British Telecom PLC (BT), who own and operate the almost the entire UK Public Switched Telephone Network (PSTN), which also incorporates the Integrated Services Digital Network (ISDN2e and ISDN30e) will be switching off ALL of these services in December 2025.

Formal announcements of this ‘fork-lift’ change were finally announced to us in the industry in 2018 of the new products and processes that Openreach had been trialling in their network to be able to withdraw PSTN/ISDN services and thus, a bit like ‘Making Tax Digital’, all equipment connected to a pure ‘Copper’ network and is reliant on a ‘Dial Tone’ will, in effect, stop working.

*Voice over Internet Protocol (VoIP) and Session Initiation Protocol (SIP) is the replacement technology behind the ability of making a simple phone call from desk or DECT (cordless) handset. Both are based on Internet Protocol (IP)

But before we get to that, lets take a closer look at how the BIG SWITCH OFF will affect homes and business in the UK.

Many elderly people still don’t have Broadband as we know it. They still have a standard, analogue line, delivered to there home by a standard copper pair and the wires go straight into a wall sockets (Network Terminating Equipment / NTE), with a phone plugged in. A phone number is associated with the service, generated from the PSTN (BT) exchange. A caller dials the number at one end and the handset rings at the other.

This scenario is the same for Nurse Call systems, PSTN lines in elevators (Lift Lines) and many other single product devices such as older Alarm Systems that used a service known as Redcare.

The vast majority of PDQ (Credit Card) machines are also connected to a standard phone line, which can be upgraded to use Wi-Fi / Internet connection, talk to your provider but do this as part of an overall project network project as now, Cyber Security comes in to the equation.

There are thousands of older, hardware-based Telephone Systems (PBXs / PABXs) in use, all connected either ISDN2e or ISDN30e services that are the digital side of the PSTN infrastructure.

There are also tens of thousands of Broadband services that are underpinned on PSTN line, with a working phone number attached. You may see invoices with a charge for the phone line and charge for the broadband against the same phone number. This type of service is part of the switch off.

So, what are the alternatives I hear you ask?

Since 2018/9 most new fibre based Broadband services that would have been installed (or should have been installed) have no ‘Dial Tone’, although the NTE is exactly the same as the current set up. I.e., the box on the wall still has the standard phone outlet but is not in use. This applies to all areas where Fibre-to-the-Cabinet (FTTC) services have been deployed. ‘Pure’ Broadband services are data only and do not allow standard phone calls unless a VoIP service (or SIP services terminating on an IP PBX) is subscribed to by a ‘Hosted Phone’ service provider.

This is not the same as full fibre (Fibre-to-the-Premises / FTTP), which is being laid from the BT Exchanges directly to your doorstep. This service accommodates up to 1 Gigabit per second (1Gbps) or 1000 Megabits per second (1000Mbps) data transfer rates and now multiple private companies are also laying their own fibre services to compete with the Openreach service. Companies line Virgin Media and City Fibre are completely independent, own and operate their own networks, fibre exchanges and infrastructure set up.   

When it comes to the ‘cellular’ / mobile networks, we have used Over the Top (OTT) Apps on our smartphones for a few years now. Apps like Facebook Messenger, WhatsApp and even Twitter all use the mobile DATA connection (not the voice side) of the Mobile Networks to initiate a voice call, hence classed as VoIP technology but, you still need the SIM card for standard voice calls, i.e., mobile to mobile or ‘landline’ number, unless you use the smartphone purely on ‘Wi-Fi’ from a broadband connection.

The end of the Copper pair?

The humble two-wire copper or copper-pair technology for making and receiving phone calls, that has served the UK so well for generations is finally set to be retired and VoIP is set to be the norm. The 50 volts exchange equipment that generates the ‘PSTN’ dial-tone and the 90 volts exchange equipment generate the ISDN2e / 30e dial tone are specifically the two technologies that ‘the big switch off’ refers to.

The physical copper pair for now, will carry SoGEA (FTTC minus dial-tone) broadband technology until UK PLC has fibre to the premises to every home and small business and is suitable for VoIP for up to approximately 20 people. After this point, ‘private’ fibre / Leased Line technology is a much more stable connection for VoIP.

Seeking Good Advice

Now is the time to review what types of phone lines and broadband services you have in your business as there are so many variations and factors to take into consideration.

There is not long to go now until December 2025 and there is no guarantee that Openreach will delay any PSTN switch-off for the reasons mentioned above about phone lines that special types applications other than making a phone call.

We recommend that you seek specialist advice if you are using any standard phone lines and especially if you have a telephone system such as Avaya, Mitel, Alcatel-Lucent, Nortel, Panasonic, Samsung, Shortel, Toshiba to name but a few.

There are around 50 (more or less) VoIP / SIP products and services on the market so the key element to choosing a new system is asking yourself, “does our current system fulfil our business practices?”

If the answer is yes, then look for those features first and then add the extras that modern VoIP / SIP functionality can bring to enhance those business processes.

Until next time –

About the Author - Pritesh Ganatra FITP

Pritesh started his career in 1990 in the Consumer Electronics industry, initially selling consumer ... Read More