Hardware & Endpoints
IP Phone
By Myroslav Orshak · operates licensed carrier infrastructure · Updated September 2026
An IP phone is a desk phone that plugs into your computer network instead of a phone jack. IP phone, SIP phone, and VoIP phone all mean the same thing, which is the most common source of confusion when buying one.
How it works
Physically it looks like an ordinary desk phone. Inside it is a small computer: it connects to your network by cable or Wi-Fi, signs in to your phone service with a username and password, converts your voice into data, and sends it over the internet. There is no phone line involved at any point.
Most models have two network sockets, which is the detail that makes installation tidy. One goes to the wall and the other to your computer, so a desk that had a network cable and a phone cable now needs only the network cable. If your network switch supports PoE, that same cable also powers the phone and the power adapter disappears too.
Why it matters
The names matter because they are how vendors confuse buyers. A shop may list the same handset as an IP phone, a SIP phone and a VoIP phone at three prices. What actually determines whether a phone works with your service is whether it supports the SIP standard, which essentially all of them do, and whether your provider supports that model.
The one genuine buying trap is locked hardware. Phones supplied by a provider are often configured so they only work with that provider, so when you switch services the handsets become paperweights. Ask before you buy whether the phones are locked, because it quietly turns a hardware purchase into a reason not to leave.
IP phone describes how it connects, SIP phone describes the signaling standard it speaks, and VoIP phone describes what it is for. In practice they are the same device, and a phone that supports SIP should work with any provider that accepts your own hardware.
Related terms
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Compare systems and their hardware →Frequently asked questions
Is a SIP phone the same as an IP phone?
Yes. The words describe different aspects of the same device — how it connects, what language it speaks, what it does — and vendors use them interchangeably. Do not pay more for one label than another.
Can I use my own phones with any provider?
Usually, if the handset supports SIP and is not locked. Ask two questions before buying: does the provider support this model, and is the phone locked to whoever sold it? A locked phone works with exactly one service and is worthless if you switch.
Do I need desk phones at all?
Increasingly not. A softphone app on a computer or mobile does the same job at no hardware cost, and works anywhere. Desk phones still win where people share a workspace, take calls all day, or need a phone that works without a computer — reception, warehouses, front counters.
What should I look for when buying one?
PoE support so one cable does everything, a pass-through network socket for the computer, enough programmable buttons for the lines people actually use, and a headset port if anyone is on calls for hours. Screen size and color matter far less than any of these.