What does VoIP stand for? It stands for Voice over Internet Protocol, the technology that carries phone calls over an internet connection instead of a traditional copper phone line. Your voice is turned into small packets of data, sent across the network and turned back into sound on the other end.
If you have made a call through a video meeting tool, used a desk phone that plugs into a network jack, or kept a home phone number with your internet service, you have used VoIP. Many business phone systems now run on it.
Quick facts
Stands for
Voice over Internet ProtocolType
Acronym, often said "voyp"Also written
VoIP (most common), VOIPNeeds
An internet connection and a VoIP phone, adapter or appReplaces
Landlines on the old public switched telephone networkRelated terms
IP, SIP, IVR, LAN
What does VoIP stand for, word by word?
- Voice: the sound of your call
- over: carried on top of
- Internet Protocol: the addressing system that moves data around networks, the same IP found in an IP address
The usual spelling is VoIP, with a small o, because "over" is a minor word. VOIP in all capitals is also seen, especially in forms and lists. People say it as one word, "voyp," or spell out "V O I P." Both are correct, so it can be filed as an acronym or an initialism.
How a VoIP call travels
- A microphone picks up your voice.
- The phone or app converts the sound to digital data and squeezes it with a codec, a program that shrinks audio.
- The data is split into packets and sent through your LAN and out to the internet.
- A VoIP provider routes the call. If the other person is on a regular phone line, the provider hands the call over to the phone network.
- The receiving device puts the packets back in order and plays the sound.
The whole trip takes less than a second. If packets arrive late or out of order, you hear choppy audio, echo or a short delay, which network staff call latency and jitter.
Ways people use VoIP
| Setup | What you use | Typical user |
|---|---|---|
| Softphone | An app on a computer or phone | Remote workers, travelers |
| IP desk phone | A phone that plugs into a network port | Offices and call centers |
| Phone adapter | A small box that connects a regular phone to the router | Homes keeping an old handset |
| Wi-Fi calling | A mobile phone placing calls over a wireless network | Places with weak cell signal |
| Hosted business system | A provider runs the phone system online | Small and midsize companies |
New hire email: "Your VoIP extension is 4127. Log in to the softphone app and your desk number will ring on your laptop." Here the office phone line lives in software rather than in a wall jack.
Business systems often add an automated menu, known as IVR, that says "press 1 for billing."
Pros and trade-offs
Why people switch: one connection can carry both data and calls, numbers can follow you to any device, and features like voicemail to email, call recording and ring groups are often built in.
What to watch:
- Power and internet outages: if the router or modem goes down, the phone usually does too, unless there is a battery backup.
- Emergency calls: a VoIP line may not know your exact location. Keep your registered address up to date with the provider so emergency calls go to the right place.
- Call quality: a slow or crowded connection hurts audio. A wired connection or a router that gives voice traffic priority helps.
Using VoIP in a sentence
- "We moved the whole office to VoIP and dropped the old phone lines."
- "My VoIP calls cut out whenever someone streams video upstairs."
- "The adapter lets the kitchen phone work as a VoIP line."
- "Is that number a mobile or a VoIP number?"
For more networking terms like ISP and Wi-Fi, browse the tech acronyms list.
Questions people ask
How do you pronounce VoIP?
Most people say "voyp," one syllable that sounds like "void" with a p in place of the d. Spelling it out as V O I P is also common, especially in tech support.
Is VoIP the same as Wi-Fi calling?
Wi-Fi calling is one kind of VoIP. It lets a mobile phone place calls over a wireless network instead of a cell tower.
Do I need a special phone for VoIP?
Not always. You can use an app on a computer or phone, a dedicated IP phone, or a small adapter that connects a regular phone to your router.
Does VoIP work during a power outage?
Usually not, unless your modem, router and phone have backup power. Many people keep a charged mobile phone for that reason.
What is a VoIP number?
It is a phone number assigned by a VoIP provider rather than tied to a physical line. It works like any other number for calling and texting.