In the modern world of communications, the Public Switched Telephone Network (PSTN) is often taken for granted; what can we do to prepare for the PSTN switch off?
Many of us take PSTN for granted. You pick up your mobile phone, dial a number, and are connected to somebody within an organisation without a thought of how that call gets there.
What is the PSTN switch off?
According to BT, “The Public Switch Telephone Network (PSTN) will close in December 2025.
“By then, every phone line in the UK will have moved to a fully digital network that uses Internet Protocol (IP) across a fibre-based service.
“This won’t just affect voice services, and it may also mean you need to upgrade your broadband.
“Any equipment that currently uses the PSTN will stop working: alarms, EPOS machines, door entry systems, CCTV, faxes, and so on.
“The Integrated Services Digital Network (ISDN) will also stop working.”
PSTN services for Private Branch Exchange
Telephony teams have procured PSTN services for their Private Branch Exchange (PBX) environments, and apart from renegotiating a new deal at the end of a contract or adding or reducing capacity, they have perhaps not spared any more attention to the connectivity they are utilising.
For many years the Integrated Services Digital Network (ISDN) has been the standard and trusted connectivity to the PSTN for PBX environments. Even with the introduction of Internet Protocol (IP) based phone systems, ISDN has still been the go-to choice to provide either the main PSTN connectivity or a backup to the newer options of Session Initiation Protocol (SIP).
It often comes in the form of a physical copper cable that’s plugged into a gateway or a line card, and if there is a little green light next to it that usually means everything is in good working order.
But by 2025, Openreach will be switching off the UK’s PSTN and migrating all customers to internet-enabled telecommunications. The legacy PSTN technology was never designed to manage the speed or the integrated signalling systems to carry voice, video and data, and so it’s no longer fit for purpose.
Many organisations have continued to utilise ISDN technology, but with 2025 being just two years away, now is the time to be giving that PSTN connectivity some serious thought and attention.
Adopting SIP as a solution
The replacement for ISDN comes in the form of SIP Trunking. SIP Trunking will still provide that PSTN connectivity, but rather than being over a physical copper cable, it is delivered over an IP network. SIP Trunking will continue to deliver inbound and outbound calls in exactly the same way that ISDN has, but it also allows for additional features and greater resilience and flexibility than traditional telephony.
Switching to SIP Trunking gives organisations the option to futureproof their existing hardware
Switching to SIP Trunking gives organisations the option to futureproof their existing hardware and make it compatible with internet-enabled telephony solutions. Once the PSTN is switched off, legacy telephones will no longer work, so if organisations are keen to keep their current equipment, then opting for SIP trunking is essential.
Not only will this allow them to take advantage of integrated communications, including messaging, presence, and video. It will enable organisations to integrate infrastructure across voice, connectivity, and security, providing a robust network for both internal and external communication.
Experienced suppliers can deliver SIP channels into most on-premise PBX environments, along with connectivity into cloud services such as Cisco Webex Calling or Microsoft Teams. This flexibility can allow a single PSTN service to be consumed even when an organisation is planning a migration to cloud telephony services.
This, in turn, reduces the complexity of migration activities around Direct Dialling In (DDI) porting, Command Line Interface (CLI) presentation and reachability between platforms.
For public sector organisations, SIP Trunking can be delivered over different types of connectivity, including but not limited to the internet, Health and Social Care Networks (HSCN), private data circuits or existing Multiprotocol Label Switching (MPLS) services in a highly resilient manner, so that healthcare and emergency service organisations can continue to communicate effectively.
The impact of the switch-off will vary between organisations and depend on how reliant they are on PSTN and ISDN services. It’s important to review and identify all the hardware and functions that are connected to and working through the phone lines, this includes things like lift phones, fax machines, CCTV systems and even panic alarms.
Planning for the 2023 PSTN switch off
While the service will be switched off by 2025, there are other key dates to be aware of that are fast approaching. Openreach will stop selling PSTN and ISDN services to new customers by September 2023, and there will be no upgrades or additional features available to existing customers after this time.
Although the finish line for the PSTN switch-off may seem a long way away, getting prepared now is key to success. Organisations need to upgrade to internet solutions ahead of this deadline to ensure continuity of service.
By looking at the services that need to be migrated now, you will avoid any last-minute panic or long lead times for the installation of new services. It also gives organisations the opportunity to take advantage of all the benefits of SIP and Voice over Internet Protocol (VoIP) services sooner rather than later.
Being aware of when Openreach’s stop-sell policy will affect your local area and getting the right expert support will be key to future-proofing communications ahead of the PSTN switch-off.
This piece was written and provided by Jono Darlington, Collaboration Solutions Architect at Cinos.
