Aurora’s Guide to the Big Switch Off

Written on 16.02.23

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What is the Big Switch Off?

Back in 2015, BT announced their “Big Switch Off” plans for the PSTN (Public Switched Telephone Network) and ISDN (Integrated Services Digital Network) networks in favour of a single IP (Internet Protocol) core network, that would replace all legacy networks. The goal of this transition is to improve the reliability and functionality of telephony solutions and services for businesses and individuals, and to take advantage of the latest technological advancements in the field of communication.

The phase-out of the older systems has begun, with new PSTN, ISDN2, and ISDN30 services no longer being accepted by BT starting in September 2023. This change in the telecoms industry will impact businesses and they should be aware of their current solutions and consider switching to new services.

What is ISDN and PSTN?

PSTN – Public Switched Telephone Network.

It is a globally interconnected network of telephone networks that provides traditional landline telephone services. It is made up of a combination of various technologies including telephone lines, fibre optic cables, switching centres, cellular networks, satellites, and cable systems, allowing users to make voice calls to each other.

ISDN – Integrated Services Digital Network.

This digital transmissions network was then introduced in the 1980’s by BT and allowed for faster communication speeds, better call quality, and more efficient use of phone lines compared to the analog PSTN. It also enabled multiple channels to be used simultaneously over a single line for voice, data, and video communication, making it a popular choice for businesses. However, with the rise of internet-based communication technologies like VoIP, ISDN is gradually being phased out and replaced by more modern solutions.


Why are the ISDN/PSTN Lines Being Switched Off?

Traditional ISDN and PSTN lines offer little flexibility and tie businesses down to their physical locations. Also, due to the advancements in IP telephony and the increased demand for modern communication technologies, this old technology just can’t keep up the demands of today’s businesses for faster, more efficient and cost-effective communications. The decrease in demand for legacy systems and the growth of IP telephony has led BT to phase out the PSTN and ISDN networks in favour of IP voice services such a VoIP and SIP.


How will the Switch Off Affect My Business?

The switch-off of PSTN and ISDN will impact businesses that are still using these technologies for their communication needs. There are over two million businesses are still relying on ISDN connections and will need to assess their options and upgrade to modern communication solutions. So you’re not alone in this migration!

With the phase-out already well underway, it’s important for businesses to act now and evaluate their current solutions to avoid potential disruption to their communications.


What Options are Available to Me?

There are two main options for businesses moving to IP telephony:

SIP Trunking

SIP Trunking uses an on-site internet connection and PBX to make and receive calls over the internet, eliminating the need for a physical phone line.

Hosted Telephony Solutions

A Hosted Phone System, also known as Hosted PBX, is a completely cloud-based solution that does not require any physical hardware. With this option, calls are made over VoIP (Voice over Internet Protocol) and all that is needed is an internet connection, making it ideal for remote workers.

Both options provide a reliable and efficient means of communication for businesses and it is important to consider the specific needs of a business when choosing between the two.


What Do I Need to Consider?

At Aurora, we recommend you consider the following before making the change:

  1. Evaluate your current system

When considering switching your phone system, the size of your business and the existing hardware you use should be taken into account.

If you’re a small business, a fully hosted solution might be a good option due to its low costs and ease of management as you don’t have to commit to a phone system on location.

For a larger business who already own an on-site PBX, it’s important to ensure your PBX supports IP telephony if you’re considering a SIP solution. If not, a hosted solution may be a more cost-effective option.

  1. Connectivity

Can your internet connection deliver VoIP? It’s important to ensure you have a reliable and fast connectivity for your new phone system to ensure smooth communication with your customers.

FTTP (Fibre to the Premises) and SoGEA (Single Order Generic Ethernet Access) are two options that provide high-speed connectivity and guaranteed speeds, making them suitable for businesses of all sizes.

  1. Number Porting

It’s also important to ensure that your new system supports number porting and to check the process and any associated costs with your provider before making the switch. Planning the number porting process can take up to a few weeks. All dependent on your number porting agreement with your previous provider, as well as the amount of numbers you want to port

Planning ahead of time will help you achieve a smooth transition to minimize any potential disruption to your business operations during the number porting process.

  1. Flexibility

A hosted solution can also enhance the productivity and efficiency of a remote workforce with features like softphone apps, which allow users to make and receive calls using their laptops or mobile devices, as well as call forwarding, allowing calls to be easily redirected to other numbers in case of remote work or other circumstances.

  1. Features

Additionally, modern phone systems often offer advanced features such as call forwarding, voicemail to email, call recording, IVR, auto-attendant and Direct Routing for Microsoft Teams. These features can improve the customer experience, increase efficiency and make running your business easier.

It’s important to note that services such as security and fire alarms, telecare devices, retail payment terminals, and equipment used for monitoring and controlling networks will also be impacted by the migration from PSTN and ISDN to a single IP core network.

We can help you to make sure the system you choose has all the features you need and is customizable to fit your business requirements. It’s also important to choose a system with the capability to add new features in the future as your business evolves.


How Aurora Can Help You Switch Off:

At Aurora we provide great pricing on our cloud telephony solutions from a range of providers:

Gamma Horizon

It provides a comprehensive suite of features, including voice, video, chat, and screen-sharing, that can be accessed from any device, including desktop, laptop, tablet, or smartphone. With Horizon, you can telephony solutions are easy – from a single platform, from call handling and routing to voicemail and call analytics. Additionally, it integrates seamlessly with your existing IT infrastructure, making it easy to set up and use. The scalability of Horizon makes it an ideal solution for businesses of all sizes, as it can grow with your business as your communication needs change.


Horizon Collaborate

Horizon Collaborate provides a seamless integration with the Horizon hosted PBX system to offer a unified communication experience with all the telephony features and functions. The result is a powerful and efficient tool that helps you manage your communication activity, maximize team productivity and reduce call costs.


Microsoft Teams Direct Routing

This allows you to leverage the power of Teams for your telephony solutions without the need for additional hardware or licensing costs, providing a cost-effective solution for organisations of all sizes. With Direct Routing, you have complete control over your telephony solutions, including call routing, and can scale and manage them according to your needs, making it a flexible and versatile solution for modern communication needs.


Gamma Horizon for Teams

This allows customers to take advantage of their existing Microsoft infrastructure with Horizon to support complex business voice requirements, all provisioned within the new Gamma Voice app.

This feature-rich solution is a cost-effective alternative to Microsoft Calling Plans, and includes advanced features such as Business Call Recording, Hunt Groups, and Auto Attendant.


SIP Trunks

SIP Trunking uses internet protocols to connect a business’ voice over IP (VoIP) phone system to the public switched telephone network (PSTN), allowing businesses to make and receive telephone calls over the internet. SIP Trunks provide the ability to make and receive calls over multiple channels using a single connection, reducing costs and increasing flexibility compared to traditional ISDN lines.


Phone Line +

PhoneLine+ has been specifically designed to replace your traditional landline service using VoIP technology to deliver voice calls over the broadband network, all at a highly competitive price.

PhoneLine+ can be accessed on a choice of devices including computers, tablets, mobile phones and IP handsets, or we can provide an adaptor for your current phone, so there is no need to invest in new equipment unless you want to. It supports all the key features expected of a traditional telephone line including voicemail, call divert and call hold, but without paying more, PhoneLine+ provides extra features designed to make your life easier.


For more information on an array of various workflow solutions, arrange a visit or call us on 020 7503 3020 or e-mail at