1. Inventory every line
Not just the ones people ring in on. Every line the building pays for, including the lift phone, the alarm dialler and the line in the stockroom nobody has used for years.
Overview
The work is not hard. Leaving it late is what hurts
Two things are going away: PSTN, the ordinary analogue line, and ISDN, the digital blocks of channels most businesses use to feed an on-site phone system. The copper stays; the voice service riding on it does not. After that, voice runs as SIP over broadband or a dedicated circuit.
The list of things affected is longer than most people expect. Lift emergency phones, alarm diallers, door entry panels, card terminals on dial-up fallback and franking machines all dial over that same voice path, and each needs its own answer. The phone system itself usually needs configuration rather than replacement.
The risk is not technical, it is scheduling. As regional stop-sell dates arrive, installers get busier and porting queues get longer, and a job that takes a fortnight planned takes a month rushed. Starting with an audit costs an afternoon and settles everything else.
Full line auditincluding the ones nobody remembers
Numbers keptported, never released
Parallel runningold and new live together
What's included
How we run a migration
In this order, every time. The last step is the one that cannot be undone.
2. List the numbers that matter
The ones on your website, your vehicles and your customers' address books. Those get ported; the rest are usually not worth carrying.
3. Check what the PBX supports
Make, model, firmware. The answer decides whether this is a configuration change or a replacement — and it is usually configuration.
4. Size the connection
Concurrent calls, not headcount. We size it from your call records so you are not paying for capacity you never reach.
5. Run both in parallel
SIP goes in alongside the old lines and a few extensions move across. A fortnight of real calls proves the path before anything is committed.
6. Port the numbers last
Only once calls are proven. Then, and only then, the old service is ceased — cancelling first releases the number and it may never come back.
FAQ
Questions about the switch-off
The national programme has already been rescheduled once, and regional stop-sell dates run ahead of the national date. Ask your line provider for the date that applies to your exchange rather than working from a headline figure — and treat any supplier quoting urgency without a specific date for your site with caution.
No. If your line already carries broadband it carries on doing so. What changes is the voice service running alongside it. The letters people receive rarely make that distinction clearly.
Usually not, and this is where money gets wasted. Any PBX that speaks SIP can be fed by a SIP trunk instead of ISDN, and most systems installed in the last fifteen years do. We check before you spend anything.
Both need a plan of their own — they dial over the voice path of a copper line, so they are affected even though nobody thinks of them as phones. We include them in the audit and tell you which need a replacement device and which can move to SIP.
Related
Other services we provide
UK SIP Trunking
The replacement for ISDN: your PBX, connected over your own broadband.
UK DIDs — Landline & Mobile
Geographic and mobile numbers delivered over SIP to your PBX.
Asterisk PBX Installation
On-premises or cloud builds, fully configured and documented.
UK Tier-1 Voice Routes
Premium UK termination on Pay As You Go terms, billed per second.
IVR Solutions
Multi-level menus, time conditions and routing built around your team.
Not sure what you are still running?
Send us a recent phone bill and we will tell you which lines are affected and what replacing them involves.