The UK’s legacy phone network (PSTN) — including ISDN services — is being retired. If your business still relies on analogue phone lines or ISDN, you’ll need to move to an IP-based alternative (such as hosted VoIP or SIP) to avoid disruption.
Key deadline: the PSTN/ISDN switch-off completes on 31 January 2027.
Important: many customers are being moved earlier, and new orders/changes to some legacy products have already been restricted (e.g., Openreach WLR stopped selling from 5 September 2023).
Get a Free Line Check / Quote
Is your business ready for the Big PSTN Switch Off? Whether you are a new or current customer, a partner, or potential partner, Ocean Telecom is here to assist you with the PSTN Switch-off. Get in touch with us today to explore your options, address your questions, and ensure a smooth transition into the digital era.
What is PSTN — and what does “switch-off” mean?
PSTN (Public Switched Telephone Network) is the traditional copper-based telephone system used for analogue landlines.
ISDN is an older digital service also delivered over legacy infrastructure.
The switch-off means these legacy services will no longer operate as the industry moves to modern IP-based communications (calls delivered over broadband/fibre).
What could be affected (it’s not just phones)
Many businesses are surprised to learn that a “phone line” can support other services too. You may be affected if you have:
- Analogue phone lines / “line rental” services
- ISDN2 / ISDN30 connected to an older PBX
- Broadband services linked to a traditional phone line
- Card payment terminals / EPOS
- Alarm diallers (intruder alarms, fire/telecare diallers)
- Door entry / gate systems
- Lift emergency lines
- CCTV/monitoring lines
- Fax lines (where still used)
This is especially common in micro businesses (takeaways, salons, cafes, independent shops) where the setup has “just worked” for years.
Key dates you should know
- 5 September 2023: Openreach stopped selling new WLR (Wholesale Line Rental) products nationally (“stop sell”).
- 31 January 2027: PSTN/ISDN switch-off completion date (legacy services stop).
Because migrations are happening ahead of the final deadline, the safest approach is to audit now, then schedule a planned migration.
How to check if your business is on legacy services
You’re more likely to be affected if:
- Your bill includes terms like WLR, PSTN, analogue line, ISDN2, ISDN30, or line rental
- You have an older PBX connected via ISDN
- You have an alarm, EPOS/card machine, or door entry that “dials out” over a phone line
- You have a dedicated lift line
If you’re unsure, Ocean Telecom can quickly confirm what you have and what needs to change.
What to replace PSTN/ISDN with (your options)
The best solution depends on your current setup, number of users, and any connected “special services”.
1) Hosted VoIP (Cloud Phone System)
Ideal for most SMEs. Calls run over IP with modern features like auto-attendant, hunt groups, call recording options, reporting, mobile/desktop apps, and easy scaling.
2) SIP Trunks
If you have an existing phone system you want to keep (and it’s compatible), SIP can replace ISDN while retaining on-site PBX functionality.
3) Connectivity upgrades (where needed)
VoIP reliability depends on good internet. If your connectivity isn’t strong enough, Ocean Telecom can advise on upgrades and resilience options.
4) Special services migration
For alarms, EPOS, lifts and monitoring devices, you may need an IP-capable replacement or reconfiguration. We’ll help you identify what’s connected and what action is required.
What a typical migration looks like
- Line check & audit – confirm all lines and anything connected to them
- Recommendation & quote – choose the best-fit option (VoIP/SIP)
- Plan the cutover – pick a date that avoids disruption
- Install & configure – set up users/devices and test
- Number porting – keep your existing numbers where possible
- Go-live & support – ongoing help once you’re live
Power cuts & resilience
Because IP calling relies on broadband/power, critical lines may need resilience (e.g., backup connectivity or battery backup). Ocean Telecom can advise on the right approach for your risk level and budget.
FAQs
Get a Free Line Check / Quote
Don’t wait for the PSTN switch off to become an urgent issue. Take the first step today by reaching out to Ocean Telecom. Our team is ready to provide you with the information and advice you need to move your business forward confidently. Contact Ocean Telecom to discuss how they can help your business embrace the future of telecommunications, staying ahead in a rapidly evolving digital world. Our team can help:
- Confirm what lines/services you have
- Identify any at-risk devices (phones, broadband, alarms, EPOS, lifts)
- Recommend the right upgrade route (VoIP or SIP)
- Provide a clear quote + timeline
