SIP trunking for reliable business calling
Telappliant is a UK and London SIP trunk provider for businesses keeping an on-premise or hybrid PBX: UK numbers, managed porting, resilient routing and Microsoft Teams Direct Routing.
What usually pushes a business off its current lines
Most of the businesses we port are not unhappy with their phone system. They are unhappy with what sits underneath it: ISDN channels they pay for whether or not anyone calls, a provider who treats a fault as someone else's problem, or a renewal notice that arrived with a number on it nobody can explain.
- BT is retiring ISDN and analogue lines, so the decision has a deadline attached whether you make it or not.
- Per-channel line rental is charged on your busiest hour, every hour of the year.
- Faults get bounced between the PBX maintainer, the line provider and the network provider.
- Adding channels for a busy season means an order, a lead time and often a new contract term.
What a Telappliant SIP trunk includes
The core capabilities you get out of the box.
What sip trunking for reliable business calling looks like in real UK operations.
Channels matched to demand
Add or remove channels as call volumes change, without an engineer visit or a new contract each time.
Managed number porting
We plan and run the port of your existing numbers, booked into a window that suits your call traffic.
Resilient routing
Calls reroute automatically if a site or connection fails, so a fault at one office does not silence it.
Microsoft Teams Direct Routing
Carrier-grade PSTN calling for Microsoft Teams Phone.
UK engineering support
The people who answer know the platform your trunks run on.
Clear call pricing
Tariffs and bundles set out in advance, with spend caps so fraud or misconfiguration cannot turn into a large bill.
Running Microsoft Teams?
Our SIP trunks power Microsoft Teams Phone through Direct Routing - keep your existing numbers, get inclusive UK minutes and a managed SBC, without Microsoft Calling Plans.
Switching from your current provider
Planned around your call traffic, so the business keeps answering the phone throughout.
- 01
Compatibility check, before anything is ordered
We confirm what your PBX and connectivity can support, and quote against real call volumes where you can share recent bills. We have connected to most systems still in UK use: Avaya, Mitel, Cisco, 3CX and others.
- 02
Pilot on a small set of numbers
A handful of numbers or channels goes live first, so call quality and failover are proven on your network before the main port is booked.
- 03
Port day, inside an agreed window
Numbers move in a low-traffic window you choose. Inbound calls keep working on the old route until the port completes, and there is a fallback plan if the losing provider misses the date.
- 04
First month review
Usage, fraud alerts and spend caps are visible from day one, and we sit down with you after the first full month to check the channel count against what actually happened.
Notice periods on your existing contract are yours to serve, but we will read the terms with you and time the port so you are not paying twice.
Who does what
We handle
- The port itself, including chasing the losing provider
- PBX interoperability testing and trunk configuration
- Failover routing, so a site outage does not silence inbound calls
- Fraud monitoring and the spend caps that go with it
- One support line for trunks, numbers and connectivity together
Stays with you
- Your PBX licensing, hardware and its maintenance contract
- Serving out any notice period on your current voice contract
- Internal call flows and who answers which number
- Telling us in advance about campaigns that will spike call volume
Who SIP trunking is still right for
SIP is not the newest way to make calls, but for the right estate it is the most sensible one.
Engineered, measured and reviewed by one integrated team that runs this every day.
A PBX with life left in it
If your Avaya, Mitel, Cisco or 3CX system still does the job, SIP keeps it useful without ripping it out.
Several sites, one account
Trunks, numbers and call plans consolidated across sites, with per-site reporting - useful when a London head office and regional branches share one provider.
Contact centres and diallers
High call volumes, with channels that burst when campaigns peak rather than a fixed ceiling.
A migration path, not a cliff edge
Many customers run SIP for the PBX and Teams Direct Routing side by side, then move users to the cloud when contracts or hardware dictate, and not before.
When SIP is the wrong answer
If your PBX is end of life, or you want calling features without owning a phone system at all, a cloud phone system will serve you better. We will tell you which side of that line you sit on.
What changes once your numbers move
What changes for your customers, your team and your numbers.
Outcomes our customers see month on month, not just on day one.
Lower running costs
No per-channel ISDN line rental, and call rates usually drop with it. We show the comparison against your actual bills before you commit to anything.
Numbers without geography
Keep your numbers wherever the business moves, and add area codes where you want a local presence.
Continuity during change
Office moves and PBX upgrades stop threatening the phone service, because the numbers live on the network rather than in the building.
No supplier ping-pong
Trunks, numbers, connectivity and support from one team, so faults cannot be bounced between providers.
SIP trunking questions, answered plainly
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Industries we work with
Talk to us about sip trunking for reliable business calling
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