VoIP vs. landline: what actually changes when you switch
Internet phone service and a traditional landline both ring the phone on your kitchen wall. Here’s how they differ in cost, reliability, 911 and features, without the jargon.
The short answer
A landline carries your calls over the phone company’s own wires. VoIP, short for voice over internet protocol, carries them over your internet connection. For most homes and small businesses the phone looks and sounds the same either way. What changes is what the phone depends on: a VoIP line needs power and internet, and in return it can ring your cell, write out your voicemail and screen spam before it rings.
How a landline works
A traditional landline is a pair of copper wires running from the phone company to your house. The line carries a small current of its own, which is why a simple corded phone often keeps working when the power goes out.
Copper networks are getting old, and many phone companies are replacing them with fiber or internet-based service. If your phone company has upgraded your line in recent years, your “landline” may already be digital, with a box in the house that needs power.
How VoIP works
VoIP turns your voice into data and sends it over the internet, the same way a video call does. You can use it three ways:
- With the phones you already own, plugged into a small phone adapter that connects to your internet router.
- With desk phones or cordless handsets built for internet calling.
- In an app on your cell phone or computer, with your home or business number on screen.
Each call uses roughly 100 kilobits per second in each direction, so almost any home broadband connection has plenty of room.
Side by side
| Landline | VoIP | |
|---|---|---|
| How calls travel | The phone company’s wires | Your internet connection |
| What you need | A phone line and a phone | Internet, plus an adapter, an internet phone or the app |
| Your number | Tied to the line at your address | Moves with you, and can ring several phones at once |
| In a power outage | A corded phone on copper often still works | Needs power for the router and adapter, or a battery backup |
| 911 | Sends the line’s address automatically | Sends the address you register, so keep it up to date |
| Voicemail | Usually dial in to listen | Can be written out and sent to your email or the app |
| Spam | Basic blocking, if any | Screening, labels and block lists |
| Cost | Often the most expensive way to keep a home phone | Often less, with features included |
What happens in a power or internet outage
This is the biggest practical difference. A VoIP phone works only while your router, your modem and the phone adapter have power and internet.
There are simple ways to cover it:
- A battery backup (often called a UPS) for the router, modem and adapter keeps calls working through short outages.
- The app on your cell can make and take calls with your home number over mobile data while the house is offline.
- Call forwarding can send calls to your cell when the line can’t be reached.
If someone in the house depends on the phone for medical reasons, plan for outages before you switch: a battery backup and a charged cell phone are the basics.
911 on VoIP
A landline’s address is fixed to the wire, so 911 knows where you are. An internet phone could be anywhere, so your provider asks for the address where the phone is used and sends it with every 911 call. That makes two habits important: give the right address when you sign up, and update it before you use the phone somewhere new.
When you’re away from home, use your cell phone’s own dialer for 911 so your location goes with the call.
Will my phones and devices work?
Ordinary corded and cordless phones work through a phone adapter. A cordless set with several handsets needs only its base plugged in.
A few devices were built with copper lines in mind and are worth checking before you switch:
- Home alarm systems that call a monitoring center over the phone line.
- Medical alert pendants that dial out through the home phone.
- Fax machines, which often work better replaced by online fax.
- Dial-up modems and older card terminals.
Ask the company behind each device whether it supports internet phone service, or whether it can use a cellular or internet connection instead.
Sound quality
On a good connection, VoIP calls sound as clear as a landline, often clearer between two internet phones. Crackles and gaps usually point to the internet connection itself, or to a busy home network. Plugging the adapter straight into the router with a cable, rather than relying on Wi‑Fi, helps.
Who should switch, and who should wait
Switching makes sense if you want to keep your number for less, answer the house phone from your cell, read your voicemail or stop spam calls.
Wait, or plan first, if your internet is unreliable, if an alarm or medical device depends on the line and can’t be changed, or if you have no way to keep the router powered in an outage.
Questions to ask any provider
- Can I keep my number, and will you check before I pay?
- Will the phones I already own work?
- How do you handle 911 addresses?
- What happens to calls when my internet is down?
- Are all the prices on your website, before I sign up?