What Is VoIP and How Does It Work?

VoIP lets you make calls over the internet instead of a landline. Learn how it works, its pros and cons, key features, and how to switch.

8 min read

Published on March 4, 2026

What Is VoIP and How Does It Work?
What does VoIP stand for?

VoIP is short for Voice over Internet Protocol (VoIP). You might hear it called Voice over IP or IP telephony, but all three terms mean the same thing — calls made over the internet instead of traditional phone lines.

 

The shift away from old-school phone lines has opened the door to faster, smarter ways to stay in touch. Voice over Internet Protocol (VoIP) routes calls over the internet, giving you clearer audio, flexible setup options, and features that traditional systems struggle to match.

Adoption continues to accelerate — the latest VoIP statistics reveal that by 2034, the U.S. VoIP market is expected to reach nearly $152 billion, with the global market projected to hit $415.2 billion.

In this article, you’ll get a quick, practical look at what VoIP is, how it works, and the advantages and tradeoffs to keep in mind. We'll also cover the features that help teams communicate more efficiently.

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What is VoIP?

VoIP is a technology that lets you make phone calls using the internet instead of traditional phone lines.

Unlike regular phones, which rely on physical wires, VoIP converts your voice into digital data and sends it over the internet to the person you’re calling. It works similarly to sending an email but transmits your voice instead of text.

In a VoIP setup, the organization typically manages and maintains its own VoIP system, such as Zoom Phone, which includes the necessary hardware, software, and infrastructure. This approach can reduce costs while giving teams more flexibility in how they communicate.

How VoIP works

Illustration showing how VoIP calling works

The voice calls you make over Wi-Fi or mobile data are a simple example of VoIP in action. While many apps use this approach for personal communication, the same concept extends for professional use through an IP phone system.

Solutions like Zoom Phone use VoIP technology to provide reliable calling, business numbers, call routing, and other features that help your business manage call workflows more efficiently.

Here’s how VoIP works behind the scenes:

  1. Digitization of voice signals:The VoIP system converts analog speech signals into digital data. This conversion process makes it possible for the voice data to be transmitted over the internet in a format that computers and other digital devices can process.
  2. Packetization of data:After your voice is digitized, it’s broken down into smaller chunks called packets. Each packet contains your voice data and information about its source and destination. This packaging helps your voice data travel efficiently across the internet.
  3. Transmission over the internet: Now that your voice data is packaged into packets, it’s ready to travel across the internet. These packets move through various network devices, such as routers and switches, which help guide them to their destination.
  4. Reassembly of packets: After the packets arrive at their destination, they’re reassembled in the correct order. The system then reconstructs the original voice signal. Despite being transmitted in smaller, discrete packets, the recipient hears a seamless and clear audio transmission, just like in a traditional phone call.

What equipment do you need for VoIP?

One of VoIP's biggest practical advantages is that it requires very little hardware. Most businesses get started with:

  • A stable broadband connection (roughly 100 Kbps per user)
  • A softphone app on a computer or mobile device (often free to download)
  • Optionally, a dedicated IP phone or an analog telephone adapter (ATA) if you want to keep desk phones

No on-site PBX box, no phone technician, no expensive copper infrastructure — just an internet connection and the right software.

VoIP vs. traditional phones

VoIP and traditional landlines both handle business calling, but they work in very different ways. VoIP runs over the internet, making it easier to scale and manage, and is typically packed with features that help teams in today’s workplace communicate more efficiently.

Landlines rely on physical phone lines, which limit flexibility and make it harder to support modern workflows. Additional differences include:

Category VoIP Landlines
Startup cost Usually lower, especially for teams already using cloud tools

App download is free; optional adapter cost: $20-$50
Can be higher due to hardware ($50-$100) and on-site phone installation ($40-$100)
Monthly fees Often more predictable and budget-friendly

Per user estimate: $15-$40 + taxes/fees
Can increase with long-distance and maintenance charges

Per line estimate: $20-$60 + taxes/fees
Call quality High quality with a stable connection Consistent, backed by physical infrastructure
International calls More affordable — lower per-minute rates, often in cents Higher rates — $1+
Features Rich capabilities, including call routing, voicemail transcription, and video options Limited features
Unified communications Can support meetings, phone, and chat in one place Not designed for integrated communication
Security Enterprise-grade security and protection are normally built in Dependent on carrier systems
Other considerations Easily scalable and adaptable to changing needs Less flexible and harder to expand

 

All in all, VoIP stands out for businesses that want a flexible IP phone system with modern workplace features. Landlines still offer steady reliability, but they lack the flexibility, speed, and range of capabilities that VoIP platforms offer for everyday communication.

VoIP vs. UCaaS: what's the difference?

You'll often see VoIP and unified communications as a service (UCaaS) mentioned together. VoIP is the underlying technology that carries voice calls over the internet, while UCaaS bundles VoIP calling with video meetings, team messaging, and file sharing in one subscription. Think of VoIP as the engine and UCaaS as the full vehicle. Zoom Phone, for example, is a VoIP phone system that can be used alongside Zoom Workplace — Zoom's UCaaS platform — for integrated communications.

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Key features of a VoIP phone system

Looking for a VoIP phone system that meets all your communication needs? Here are some features that can make your business communication easier:

 

Unified communications

Imagine having all your communication tools in one place. With unified communications, you get seamless integration of meetings, phone, and Zoom Chat. It's like having a supercharged command center for your team's collaboration efforts.

Auto receptionist

An auto receptionist (sometimes called an auto attendant) greets callers and routes them to the right person or department automatically — 24/7, without requiring a dedicated front desk employee. With Zoom Phone, you can also add an AI receptionist (available as an add-on) that answers after-hours calls, books appointments, and handles common questions without any live agent involvement.

Desktop and mobile compatibility

Stay connected on the go with desktop and mobile compatibility. Whether you're at your desk or out and about, you can access your VoIP phone system from any compatible device, so you don't miss important calls.

Encryption and security

Protect your sensitive communications with encryption and robust security measures. It's like a secure vault for your calls, keeping your conversations private and confidential.

HD audio quality

VoIP delivers high-definition audio that often sounds better than a standard landline call — assuming a stable internet connection. Modern codecs and adaptive quality tools help minimize the impact of minor network fluctuations.

AI-powered productivity features

Modern VoIP platforms go well beyond basic calling. Zoom Phone, for example, includes call summary, voicemail tasks, and voicemail prioritization to help you stay focused and respond faster — so you can focus on running your business instead of reviewing call notes.

With Zoom Phone's comprehensive suite of calling features, you can enjoy a flexible, mobile cloud phone system with integrations, HD voice quality, call recording, and mobile app access.

Pros and Cons of VoIP

VoIP can transform your business communication by replacing fixed phone lines with an internet-based system that’s easier to scale, manage, and adapt. This is especially useful for teams that want a flexible setup or use a Bring Your Own Carrier (BYOC) approach, since everything runs on a cloud-based foundation.

There are also a few tradeoffs to consider, particularly surrounding connection quality. Here’s a closer look at both sides:

Pros Cons
  • Cost efficiency: Lower calling costs, especially for long-distance and international calls.
  • Flexible and scalable: Easy to add users, adjust features, or use BYOC as your needs shift.
  • Feature-rich: Call routing, voicemail transcription, analytics, video options, and more.
  • Portable and accessible: Make and receive calls from almost anywhere with internet access.
  • Integrations: Works with workplace tools to streamline communication and workflows.
  • HD audio: Clear, natural-sounding calls.
  • Lower hardware footprint: Fewer on-site devices, which can reduce energy use.
  • Internet dependence: Call quality drops when the connection is slow, unstable, or showing jitter.
  • Quality issues with poor connectivity: Low bandwidth or congestion can cause lag or dropped calls.
  • Emergency calling limitations: Can be affected by power or network outages.
  • Compatibility gaps: Older hardware or specialized systems might not integrate smoothly.
  • Regulatory requirements: Rules vary by region and may require additional configuration.

 

If your team wants modern calling features, simpler management, and room to grow, VoIP offers a strong foundation. Teams see the strongest results when VoIP is paired with a stable internet connection and a provider that fits their workflow.

Pros and cons of VoIP calling

How Zoom Phone can make VoIP work for your business

Zoom Phone is a cloud-based VoIP phone system built for the way modern teams actually work — with features that go beyond dial tone and voicemail.

Here's what sets it apart:

  • Call summary and voicemail tasks: After each call, Zoom Phone can generate a summary and surface next steps automatically — no manual notes needed.
  • Voicemail prioritization: AI scans your voicemails and surfaces the ones that need attention first, so nothing important slips through.
  • 200+ integrations: Connect Zoom Phone inside the apps your team already uses — including Salesforce, HubSpot, Microsoft Teams, and more.
  • Shared lines and call groups: Make it easy for multiple people to answer a business number so customers aren't left waiting.
  • Global PSTN coverage: Expand into markets internationally with global PSTN coverage across dozens of countries, or bring your own carrier (BYOC).
  • Up to a 99.999% uptime SLA: High-quality calling with enterprise-grade reliability and built-in security.

Zoom Phone also integrates with Zoom Workplace, our AI-first collaboration platform, so your phone system, meetings, and chat all live in one place.

For a real-world example of what's possible: Flex reduced 50–70% of circuits and infrastructure worldwide and lowered their total cost of ownership by switching to Zoom Phone.

Security and compliance support

For businesses that handle sensitive information — in healthcare, financial services, or legal — VoIP security isn't optional. Zoom Phone provides features designed to support security and compliance requirements, including E911 support to help businesses stay prepared for emergency situations. Role-based access controls enable admins to manage who can see call logs, recordings, and settings without needing deep technical expertise. For a full overview of Zoom's certifications and attestations visit our Compliance at Zoom page.

Ready to evaluate your options? Our VoIP phone buying guide walks you through hardware types, must-have features, and how to choose the right system for your business size and budget.

How to switch to VoIP in 5 easy steps

Moving to VoIP is straightforward when you break the process into clear stages. You’ll plan your needs, check your connection, choose a provider, gather any equipment, and finish setup with onboarding.

If you’ve ever spotted jitter on a speed test, you know the internet plays a role in call quality, so preparing your network early will help you get the most out of your IP voice setup.

1. Determine your needs and budget

Start by mapping out how your team communicates. Look at call volume, remote work expectations, the tools you already use, and any security rules that apply. For example, healthcare organizations that are subject to HIPAA regulations may look for a , VoIP provider that offers features such as encrypted calling and controlled access to call records.

Next, create a clear budget. Budget estimates to plan around:

  • Initial setup: Often free to $150, depending on configuration needs
  • Monthly service: Commonly $10–$30 per user
  • Equipment (IP phones, adapters, headsets): $20–$200 per device
  • Training: Usually free through online resources; live training varies
  • Add-ons (advanced analytics, call recording): $5–$15 per user

Use these estimates to compare the investment with potential gains. Many organizations see measurable cost and infrastructure improvements after switching to VoIP. For instance, Flex reduced 50%-70% of circuits and infrastructure worldwide and lowered total cost of ownership by moving to Zoom Phone.

2. Check your internet

Run a bandwidth test to see if your connection can support VoIP. You want a stable link with roughly 100 Kbps per user. If you've ever noticed jitter on a speed test, your network may need a tune-up before you switch.

If your current setup falls short, consider a small upgrade. A newer router, stronger Wi-Fi, or a different ISP help reduce dropped calls and minimize jitter during conversations.

3. Research providers

A good VoIP provider should support how your business operates today while leaving room to grow. As you compare options, look for:

  • Reliability and service availability: Consistent uptime supports uninterrupted calling and predictable performance.
  • Integrated chat platform: Keeps conversations and quick updates in one place.
  • Tool integrations: Connects VoIP with your workflow tools for simpler communication.
  • Scalability: Easy user management as staffing needs change.
  • Encryption and security: Protects sensitive conversations and supports compliance.
  • Auto receptionist: Routes callers to the right place without manual handling.

Also check for mobile app support, international calling options, and any regional limits. With Zoom Phone, you get a flexible cloud phone system built for mobility, along with helpful integrations, AI-first productivity tools, and HD voice quality. Additional VoIP phone features, such as call recording, voicemail transcription, and mobile access, can make day-to-day communication easier to manage.

4. Collect the necessary equipment

Once you choose your provider, gather what you need for smooth onboarding, including:

  • Routers: Support a stable network and consistent call quality.
  • Analog telephone adapters: Ideal if you want to keep existing desk phones.
  • IP phones: Designed for teams upgrading to dedicated VoIP hardware.
  • Headsets: Helpful for computers or softphone setups.
  • Other accessories: Based on your workspace layout and calling patterns.

5. Kick things off with your provider

Your provider will guide you through onboarding, which usually includes a quick walkthrough of features and user training. If you’re keeping your existing number, they’ll handle number porting. If not, you can share a new number across your website, email signatures, and customer channels.

Once everything’s connected, your team can make and receive calls with your new VoIP system and transition into daily use with minimal disruption.

Frequently asked questions

What does VoIP stand for?

VoIP stands for Voice over Internet Protocol. It's a technology that lets you make and receive phone calls using a broadband internet connection instead of a traditional landline or analog phone line. You may also hear it called IP telephony or internet telephony.

How much does VoIP cost?

VoIP can be very affordable. Many plans run about $10–$40 per user each month. Costs may increase if you add equipment or extra features. Setup is typically free to minimal, which makes VoIP often significantly more affordable upfront than traditional phone systems.

Can cell phones use VoIP?

Yes — many cell phones can use VoIP with apps like Zoom Workplace. When connected to Wi-Fi, these apps route calls over the internet rather than the cellular network, which can reduce costs and unlock additional calling features.

Can you keep your current phone number when switching to VoIP?

Yes. Most VoIP providers support number porting, so you can bring your existing business phone number to your new system.

Is VoIP more secure than traditional phones?

VoIP can offer stronger protection than traditional landlines when providers apply current security practices — including encryption, role-based access controls, and compliance tools. The security experience depends heavily on the provider you choose.

What's the difference between VoIP and a hosted VoIP system?

Standard VoIP describes the technology itself. A hosted VoIP system (also called a cloud phone system) means the provider manages the infrastructure for you — you just use the service. Many business VoIP solutions today, including Zoom Phone, are hosted.

Conclusion

VoIP replaces the physical phone line with an internet connection, giving your business access to advanced features, simplified management, and potential cost savings. Whether you're a solo operator or running a growing team, it's a practical upgrade that doesn't require IT expertise to set up or maintain.

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