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HomeServices › Voice Transformation

UCaaS & Business Voice UK

Migrate from legacy ISDN, PBX and traditional telephony to modern cloud-hosted communications. Reduce costs, improve flexibility and prepare for the 2027 PSTN switch-off.

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Why voice transformation is urgent

BT is switching off the Public Switched Telephone Network (PSTN) — the infrastructure that carries traditional phone calls — by January 2027. Every business using an ISDN line, a traditional PBX, or any legacy telephony will be affected. This is not optional and it is not far away.

But the PSTN switch-off is also an opportunity. Businesses that act now — rather than waiting for the deadline — can move to modern, cloud-hosted communications that are cheaper, more flexible and better for remote and hybrid working.

What does voice transformation mean?

Voice transformation typically involves migrating from one or more of the following legacy systems to a modern alternative:

Hosted UC and collaboration

Modern cloud voice platforms do far more than replace a phone line. They integrate voice, video, messaging and collaboration into a single platform — accessible from any device, anywhere. For businesses with hybrid or remote workers, this is transformative.

Open Way Technologies has access to leading hosted UC platforms through our provider network, including solutions with 100% uptime SLAs, sub-1ms jitter (PoP to PoP) and coverage across 115 countries — suitable for businesses of all sizes from SMEs to multinational enterprises.

SIP trunking as an intermediate step

If you have recently invested in a PBX and are not ready to replace it, SIP trunking can replace your ISDN lines while keeping your existing handsets and PBX in place. This is a lower-cost, lower-disruption intermediate step that still achieves PSTN compliance ahead of 2027.

What happens if we do nothing before 2027?
BT will cease to carry ISDN and PSTN calls. Your existing phone system will stop working. The switch-off is scheduled for January 2027 but some areas are being migrated earlier. Acting now gives you time to choose the right solution rather than being forced into a rushed migration.
Can we keep our existing phone numbers?
Yes — number porting allows you to keep your existing DDI numbers when migrating to a hosted voice or SIP solution. Open Way Technologies will ensure number porting is included in the migration plan.
How disruptive is the migration?
With careful planning, voice migrations can be carried out with minimal disruption — often with no downtime. The key is detailed pre-migration planning, which Open Way Technologies manages on your behalf.
What about our handsets?
Depending on the solution chosen, existing IP handsets may be reusable. Softphone applications on laptops and mobiles can also replace physical handsets, reducing hardware costs.

At a glance

Switch-off2027
Jitter<1ms PoP-PoP
Uptime SLA100%
Cost to you£0

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