When does the UK PSTN switch off?

BT Openreach is retiring the UK PSTN (WLR 2) on 31 January 2027. Every UK business landline must move to a digital service such as VoIP or full-fibre voice before that date.

What is the cheapest UK business VoIP?

Silux Call offers a free seat tier (1 user, 1 UK DDI, 30 minutes/month) and Pay-as-you-go from £0/month + £0.02 per UK landline minute, with no contract. Paid plans start at £6.95/user/month and come with a 30-day free trial.

Does Silux Call have a free trial, and do I need a credit card?

Yes. Every paid plan comes with a 30-day free trial and no credit card is required to start — most UK rivals offer only a 7 or 14-day trial, and several require a card up front. You can also stay on a permanently free seat with no card at all. Signing up takes about 60 seconds.

How quickly can I get a UK virtual landline number?

You can sign up in about 60 seconds and choose a UK virtual landline number (020, 0161, 03 or 0800) instantly — no engineer visit, no hardware and no contract. Existing numbers port across free on Plus and above, typically within 24 hours.

Can I keep my existing phone number?

Yes — Silux Call offers free UK number porting on Plus and above, typically completing in 24 hours. We support PAC and STAC porting workflows.

Does Silux Call work with Microsoft Teams?

Yes — Silux Call supports Microsoft Teams Direct Routing on the Pro tier, including a self-service onboarding wizard that issues the PowerShell snippet for your Teams admin.

Is Silux Call GDPR and HIPAA compliant?

Silux Call ships UK GDPR-compliant call recording with two-party consent flows, plus one-click HIPAA enrolment that locks 6-year retention, KMS-backed encryption, and PCI DTMF redaction. A one-click compliance report exports an auditor-ready PDF.

How does Silux Call block scam calls?

Silux Call screens every inbound call with an AI scam shield in under 0.5 seconds. Known HMRC, parcel, and account-spoof patterns are blocked before your phone rings — a feature no other UK business VoIP provider ships.

VoIP vs SIP trunk: which one does your business actually need?

When to choose a hosted VoIP service, when a SIP trunk is right, and the tax / accounting differences for UK companies.

The two terms are often used interchangeably. They are not the same. Picking the wrong one wastes money and locks you into the wrong contract for the 2027 PSTN switch-off.

Hosted VoIP, in one sentence

Hosted VoIP is a managed service: the provider runs the phone system in their cloud, you bring users and numbers. Examples: Silux Call, Yay, bOnline, Voipfone.

SIP trunk, in one sentence

A SIP trunk is a wholesale connection that points your own on-premise phone system (a 3CX server, an Asterisk box, a Mitel PBX) at the public phone network. You manage the PBX yourself, you just buy the dial-tone.

Which one for which business?

You have 1-50 users and no phone-system specialist on staff — hosted VoIP. Don't even consider a SIP trunk.
You already own a PBX you like (typical of larger SMBs with a long-running Mitel or Avaya install) — a SIP trunk lets you keep it and replace just the BT line.
You're a software vendor that needs to embed calling — neither; you want a CPaaS like Twilio or our open-API tier.
You're an MSP — Silux Call's white-label hosted VoIP is what your customers want. SIP trunks are what *you* might buy wholesale to terminate on a 3CX you host for them.

Cost comparison (UK, real numbers)

Item	Hosted VoIP (Silux Plus)	SIP trunk + on-prem PBX
Per user / month	£11.95 all-in	£3-7 (trunk) + £4-12 (PBX licence amortised)
Hardware up-front	£0	£800-£5,000 for the PBX server + handsets
IT engineer time	0 hours/month	2-8 hours/month for upgrades, security patches, capacity
5-year total (10 users)	~£7,170	~£11,500–£18,000

UK tax / accounting

Hosted VoIP is an operating expense; you deduct the £11.95/user/month against profit immediately. SIP-trunk-plus-PBX gear is normally capitalised over 5 years for HMRC purposes; talk to your accountant before signing.

The 2027 switch-off angle

Both work after the PSTN switch-off — both speak SIP over the open internet. The only thing that stops working in 2027 is the analogue copper line under WLR2; whatever you put on top of it (hosted VoIP or SIP trunk) survives.

Our take

Choose hosted VoIP unless you have a specific reason not to. Silux Call's Pro tier (£17.95) is feature-equivalent to a £40k 3CX-plus-SBC build at the 10-user scale, with no maintenance burden.