Jump to:

• How VoIP Works
• How Landlines Work
• VoIP vs. Landline: Side-by-Side
• Where VoIP Wins
• Where Landline Still Has an Edge
• The Third Option: The Phonewire Hybrid
• The Copper Retirement Changes Everything
• How to Convert Landlines to VoIP

How VoIP Works

VoIP stands for Voice over Internet Protocol. Instead of routing your voice through copper wires to a telephone company switching center, VoIP converts your voice into digital packets and transmits them over your internet connection to the recipient. At the other end, the packets are reassembled and converted back into audio.

From the user’s perspective, a VoIP call feels exactly like a regular phone call — you pick up, dial, talk, hang up. The difference is entirely in the infrastructure. Rather than a physical copper wire running from your building to a central office, VoIP calls travel over the same broadband connection your computers use for everything else.

Modern VoIP phone systems go far beyond basic calling. The internet delivery layer enables a feature set that copper landlines simply cannot replicate: auto-attendant menus, ring groups that simultaneously ring multiple extensions, voicemail to email, business texting on your office number, call recording, real-time presence indicators, mobile and desktop app extensions, and integration with CRM and business software. These features exist because VoIP is software-driven — features are added and updated like any other software, without hardware changes.

How Landlines Work

Landline telephones have operated on essentially the same principles for over a century. Your voice is converted into an electrical signal that travels through copper wires — from your building, through the telephone company’s network of underground cables and switching centers, to the person you’re calling. The connection is dedicated, physical, and point-to-point.

Traditional copper landlines — technically called POTS (Plain Old Telephone Service) — have one significant operational advantage: they draw power from the telephone network itself rather than from your building’s electrical system. This means a basic corded landline phone keeps working during a power outage, without a battery backup or generator. For businesses in areas prone to outages, or industries where phone availability is life-safety critical, this has historically been a real and legitimate advantage.

The downsides are substantial and growing. Copper landlines are expensive — typically $80–$150+ per line per month in 2026, with rates increasing as carriers accelerate their retirement of copper infrastructure. They carry one call per line, requiring multiple lines for concurrent calls. They support none of the features available on VoIP systems. And AT&T, Lumen, and other carriers are actively decommissioning copper infrastructure nationwide through 2029. In some areas, copper line rates have already spiked to thousands of dollars per month as carriers push customers off aging networks.

VoIP vs. Landline: Side-by-Side

Where VoIP Wins — Comprehensively

Cost

This is the clearest advantage and the most immediately felt. A business paying $100/month for each of 8 copper POTS lines spends $800/month on phone line service alone. The equivalent SIP trunk capacity on Phonewire’s system runs approximately $200/month — the same concurrent call capacity for 75% less. When you factor in the features included with a VoIP system that would require expensive add-ons on a legacy landline setup, the gap widens further.

Features That Change How Your Business Operates

Every feature that makes a business phone system professional — the auto-attendant that greets callers and routes them to the right department, the ring group that rings every available employee simultaneously so calls never go to voicemail unnecessarily, the voicemail that arrives in your inbox as an audio file within seconds, the mobile app that gives remote employees a full business extension on their existing cell phone — all of these are VoIP features. Copper landlines don’t support them. If you’ve ever had a phone system that did these things, it was running VoIP under the hood, even if it looked like a traditional office phone setup.

Mobile and Remote Work

A landline is physically anchored to a location. An employee working from home, traveling for business, or splitting time between two offices cannot use a copper landline extension. Phonewire’s Linkus UC app gives every employee a full business extension on their existing iPhone, Android, Mac, or Windows device — same extension number, same voicemail, same presence visibility. Outbound calls display the business number, not the employee’s personal cell. Clients call the business number, not anyone’s personal phone.

Scalability Without Infrastructure Projects

Adding a new employee to a copper landline system means ordering a new physical phone line, waiting for installation, paying a monthly line rental forever. Adding a new user on Phonewire’s VoIP system means creating an extension in the admin portal, plugging in a desk phone to the existing Ethernet port on the wall, or simply installing the mobile app. No new wiring. No carrier appointment. No delay. The same applies in reverse — reducing lines as a team contracts doesn’t require canceling physical circuits with a carrier.

CRM and Software Integration

VoIP phone systems integrate with the software your business already uses. When an inbound call arrives on a Phonewire system integrated with your CRM, the caller’s record surfaces automatically on screen. When the call ends, the call activity logs to the contact. Sales teams, service desks, and any customer-facing operation become measurably more efficient when call data and customer data exist in the same system rather than in separate silos. Copper landlines cannot do this at any price.

Where Landline Has a Legitimate Edge — and the Honest Answer

Most VoIP providers gloss over VoIP’s one real limitation. We won’t.

Traditional copper landlines draw power from the telephone company’s network, not from your building’s electrical system. A corded landline phone works during a power outage without any backup power — the carrier provides enough current to operate the handset. This is the one functional advantage of copper that VoIP cannot match through the same mechanism.

For businesses in industries where phones must stay on regardless of circumstances — emergency services, healthcare, certain manufacturing environments — this has historically been the argument for keeping at least some copper lines in service.

VoIP’s dependency extends further: it also requires a working internet connection. When your ISP has an outage, cloud-only VoIP phones go silent. No inbound calls. No outbound calls. Your main business number becomes unreachable until the internet restores.

This is the real reason many business owners hesitate before committing to VoIP. They’re not attached to copper for sentimental reasons — they’ve experienced a broadband outage before, they know it happens, and they don’t want their business phone line to be dependent on a single point of failure they don’t control.

That concern is completely valid. And it has a specific, hardware-based answer.

The Third Option: The Phonewire Hybrid System

Most discussions of VoIP vs. landline present a binary choice: get VoIP and accept the internet dependency, or keep landlines and pay more for less. This is a false choice. There’s a third option that most providers either don’t offer or don’t explain clearly.

Phonewire’s Hybrid phone system is on-premises hardware installed at your location — running on your network, not dependent on a cloud data center — with a built-in 4G LTE cellular failover module. Here is what that means in practice:

The Copper Retirement Changes the Equation

The VoIP vs. landline debate is becoming moot for a reason that has nothing to do with technology preference: copper landlines are being retired by the carriers that run them.

AT&T, Lumen, and other major carriers are actively decommissioning POTS copper infrastructure across the United States, with the sunset scheduled through 2029. This means businesses currently running copper POTS lines will eventually receive notice that their service is being discontinued — with approximately 90 days to transition. In areas where copper retirement has already begun, monthly rates have increased dramatically as carriers use pricing to accelerate migration off aging networks.

The bottom line: if your business is still on copper landlines, the decision of whether to switch to VoIP is no longer purely optional. The question is whether you make the transition on your own schedule, with time to evaluate options and plan properly, or reactively in a 90-day window when your carrier sends notice.

Phonewire handles POTS-to-VoIP migrations as part of every phone system installation. Your existing numbers port to the new system. The old copper lines stay active until cutover. Installation is completed in a single day. See the full copper retirement guide →

How to Convert Landlines to VoIP with Phonewire

The conversion process is more straightforward than most business owners expect — because Phonewire handles all of it. Here’s what the process actually looks like:

Consultation and quote. Phonewire reviews your current setup — how many lines, what equipment, call volume, team size — and produces a specific quote for the replacement system, installation, and monthly service. Same-day quote, no ranges.

Number porting. Your existing business phone numbers are submitted to port to the new system. Porting typically takes 2–5 business days and happens in the background. Your copper lines continue to function normally during the porting window — no gap in service during the transition.

Pre-configuration. Phonewire configures the new system remotely before arriving at your location — extensions programmed, auto-attendant recorded, ring groups set up, voicemail configured. The technician arrives with a system that’s ready to go, not a box of parts to figure out on-site.

Installation day. Phones are deployed, network connections verified, every extension tested. Staff training happens before the technician leaves. The number port cutover is executed — old lines release, new system goes live. The window between old and new is typically seconds.

Ongoing support. Phonewire’s U.S.-based support line is answered in under a minute. When something needs to change — a new employee, an updated greeting, a different call routing configuration — you call the same number you called to get the system installed. The same team that installed your system picks up.