Question 1

What is the difference between a SIP phone and a Teams-certified IP phone?

Accepted Answer

A SIP phone uses the open Session Initiation Protocol and works with virtually any PBX or hosted VoIP provider, whilst a Teams-certified phone runs Microsoft's own firmware and is designed specifically for Teams Phone calls. The practical difference is significant: Teams-certified models (like the Yealink MP series or Poly CCX range) give you native presence indicators, one-touch meeting join, and calendar integration — things a generic SIP phone configured for Teams simply cannot replicate cleanly. If your organisation is committed to Microsoft 365, the Teams-native route is worth the extra cost.

Question 2

Do I need PoE switches to deploy IP phones across an office?

Accepted Answer

Not necessarily, but PoE makes deployment considerably cleaner. Without PoE, each phone needs its own power adaptor and a nearby mains socket — manageable for a handful of handsets, but a real headache at scale. Most mid-range IP phones support PoE (802.3af), so if your network switches already have PoE ports, you're set. If not, a PoE injector per phone is a low-cost workaround, though a PoE switch is the tidier long-term solution for offices of 10 or more.

Question 3

How many SIP lines do I actually need?

Accepted Answer

For a typical office worker who handles one call at a time, 2–3 lines is sufficient. Receptionists and team leads who juggle multiple calls simultaneously should look at 4–6 lines. High-volume environments — call centres, busy front desks — benefit from 8–12 lines, as found on models like the Grandstream GXP2170. A common mistake is under-specifying lines for reception staff, who then find themselves unable to transfer a call without dropping another.

Question 4

Are cheap IP phones worth buying, or should I avoid them?

Accepted Answer

It depends entirely on the use case. A sub-70 £ SIP phone is perfectly adequate for a back-office employee who takes a handful of calls per day — the call quality will be fine and the features sufficient. Where budget phones let you down is in high-use scenarios: the build quality degrades faster, programmable keys are limited, and HD voice or encryption may be absent. We'd avoid the very cheapest models for receptionists or anyone on the phone for more than two hours a day. The sweet spot for most users sits between 70 £ and 115 £.

Question 5

Can I use an IP phone with any VoIP provider or PBX?

Accepted Answer

Most SIP-based IP phones are compatible with any SIP-compliant PBX or hosted VoIP provider — Asterisk, 3CX, FreePBX, RingCentral, and most UK business VoIP services all work with brands like Grandstream, Yealink, Snom, and Fanvil. The exception is Teams-certified phones, which are locked to Microsoft's platform, and Cisco phones, which are optimised for Cisco's own Unified Communications Manager. Always check the interoperability list on your PBX provider's website before purchasing in bulk.

Question 6

What does SRTP and TLS mean on an IP phone, and do I need it?

Accepted Answer

SRTP (Secure Real-time Transport Protocol) encrypts the audio stream of your calls, whilst TLS (Transport Layer Security) encrypts the signalling — essentially the call setup instructions. Together, they prevent eavesdropping on VoIP calls. For most small businesses, the risk is low, but for legal, financial, or healthcare environments handling sensitive conversations, both are essential. The good news is that most business-grade IP phones above 70 £ include SRTP and TLS 1.2 as standard — just confirm it's enabled in the phone's configuration.

Question 7

Which IP phone brands are most reliable for UK business deployments in 2026?

Accepted Answer

Yealink and Grandstream Networks are the two most consistently reliable choices for UK SME deployments, offering broad PBX compatibility, regular firmware updates, and strong value. Poly (formerly Plantronics/Polycom) is the go-to for Teams and Zoom environments. Snom has a loyal following among IT resellers for its open standards and build quality. Cisco remains excellent but commands a significant price premium that's only justified in full Cisco UC environments. Fanvil is worth considering for budget-conscious deployments where feature breadth matters more than brand recognition.

IP Phones Price Comparison

IP Phones price comparison UK