What is VoIP?
VoIP (Voice over Internet Protocol) is a technology that carries phone calls over an internet connection instead of a copper phone line. Your voice is converted into data packets, sent across the network and turned back into sound at the other end.
How it works
When you speak, a VoIP app or desk phone samples your voice, compresses it with a codec and splits it into small packets. Those packets travel over your internet connection using SIP to set up the call and RTP to carry the audio.
If the person you call is also on VoIP, the packets go all the way over the internet. If they are on a regular landline or mobile, the provider hands the call to the public telephone network through a gateway, so anyone can call you and you can call anyone.
Call quality depends on the network more than the device: enough bandwidth (about 100 kbps per call), low latency and low jitter. A stable connection matters more than raw speed.
Why it matters
01Lower cost
No phone lines to rent and no hardware to maintain. You pay per user, and calls within a country are usually included.
02Work from anywhere
The same number rings on a laptop, a desk phone or a mobile app, in the office or at home.
03Software features
Routing, recording, transcription and CRM sync come with the line instead of being bolted on.
Allo and VoIP
Allo is a VoIP phone system for teams: business numbers in 50+ countries, apps for desktop and mobile, and every call recorded, transcribed and summarized into your CRM.
Related terms
The terms that usually come up in the same conversation.
All glossary terms
SIP trunking
Virtual lines that connect a PBX to the phone network over the internet.
Read the definition
Frequently asked questions
Not quite. Wi-Fi calling is a mobile carrier feature that routes your regular mobile number over Wi-Fi. VoIP is a broader technology: a business VoIP service gives you numbers and features that live in software, independent of any SIM card.
In most cases, yes. Moving an existing number to a VoIP provider is called number porting, and it is a regulated right in the US, the UK, the EU and many other countries.
Not on the affected connection. Most VoIP services let you forward calls to a mobile number or answer on a mobile app over cellular data, so calls still reach you.