VoIP vs Landline vs Mobile for a Small Business Phone

The three options in plain terms

Every small business phone today is one of three things, or a mix of them:

• Landline. Phone service delivered by a phone company to a fixed address. Traditionally this meant a copper pair from the local exchange. Increasingly the "landline" a phone company sells is delivered over fibre and converted to a phone jack by equipment in your premises.
• VoIP. Voice over internet protocol: calls carried over an internet connection. The FCC describes it as converting your voice into a digital signal that can travel over the Internet, which is converted back when it reaches a regular phone. It can run on desk phones, an adapter for an ordinary phone, a computer, or an app on a mobile.
• Mobile. A cellular plan on a SIM in one handset.

The words blur in practice. A cable company's "home phone" is VoIP. A business VoIP number can ring mobile phones. A fibre "landline" behaves like VoIP when the power goes out. So compare on behaviour, not labels: what happens in an outage, what happens when someone dials 911, what it costs, and how many people it can reach.

Summary table

The sections below explain each row and cite the rules behind them.

Power and outages

This is the biggest practical difference, and it surprises people moving off copper.

The FCC states that line-powered traditional landline service through copper wires typically continues to work during power outages, allowing you to call 911, while fibre, coaxial cable and wireless alternatives usually need backup power such as a battery. The same guide says a battery backup improves your chances of keeping phone service for at least 24 hours during a power outage. Do not count on the provider to offer one: the FCC rule that made providers offer 8- and 24-hour backup power at the point of sale covered residential service only, sunset on 1 September 2025, and was removed from the rules in 2026 ^[1]. As of October 2026, backup power for a business line in the US is your own plan.

For VoIP, the FCC is blunt: VoIP service may not work during a power outage or when the internet connection fails or becomes overloaded. Its suggestions are a backup power supply, keeping a traditional line, or having a wireless phone as a backup.

Fibre landlines behave the same way. Bell, which is moving business customers off its copper network, tells them that business phone service, including access to 9-1-1, will not work during a power outage without a battery backup, and that services using a phone line, such as security systems, may also stop working.

Mobile phones keep working on battery as long as the local cell sites stay up, which is why the FCC lists a wireless phone as a backup for VoIP.

What to do:

• List every device that uses your phone service: main line, fax, alarm panel, card terminal, elevator phone.
• Put the modem, router and any VoIP adapter on an uninterruptible power supply (UPS).
• Decide which mobile is the outage phone, and make sure it is charged and known to staff.
• Ask your alarm company how the panel reports if your line or internet is down.
• Keep a one-page outage plan. Our business phone outage recovery worksheet is a template.

911 and location

Landline. A fixed line is tied to a service address, so the emergency centre receives the address the phone company has on file.

VoIP (US). The FCC requires providers of interconnected VoIP to provide 911 as a standard feature that customers cannot opt out of, obtain the customer's physical location before activation, provide easy ways to update it, and send the callback number and registered location with each 911 call. Even so, the FCC warns that VoIP 911 calls may not connect to the centre serving your current location, may ring an administrative line not staffed after hours, or may arrive without your number or location. The weak point is the registered address: if a VoIP phone or app moves to another site, the address on file can be wrong.

VoIP (Canada). The CRTC requires local VoIP providers to provide Basic or Enhanced 9-1-1 service and to notify customers of any 9-1-1 limitations. Its model customer notice explains that a VoIP 9-1-1 call may be forwarded to a third-party provider that routes it to the emergency centre, that callers must state their location because the operator may not have it, and that outages of power or internet, or a suspended account, can disrupt 9-1-1. It recommends keeping an alternative such as a cellular phone.

Mobile. A mobile is not tied to a service address, so whoever calls should always tell the operator where they are.

What to do:

• For every VoIP phone or app, confirm the registered address matches where it is used.
• Tell staff to give their location out loud on any emergency call.
• Put a label near each VoIP desk phone stating the address on file.

Reliability and call quality

A copper line's quality depends on the phone company's network, and it does not share capacity with your internet traffic.

VoIP depends on your internet connection. By definition, interconnected VoIP requires a broadband connection from the user's location and IP-compatible equipment. If someone uploads large files on the same connection, or the connection is unstable, calls can break up. Practical fixes are a business-grade connection, a router that gives voice traffic priority, and a second connection or cellular failover if the phone matters.

Mobile quality depends on coverage where you work. Before you rely on mobiles, walk the building, including back rooms and basements, and place test calls on each carrier your staff use.

A middle path many small businesses use: keep the business number on a provider's network and have it ring staff mobiles. Calls then do not depend on your office router or a desk phone, and if one person does not answer, the next one can.

Cost drivers

Prices vary by region, provider and promotion, and change often, so the useful comparison is what you pay for.

Regulatory costs exist on every type. The FCC notes, for example, that interconnected VoIP providers must contribute to the Universal Service Fund and the relay services fund. Ask each provider for a total monthly figure including taxes and fees before comparing.

Also price the people side. A missed call costs more than a line fee for most small businesses, so the cheapest option is not the one where calls go unanswered.

Mobile as the business phone: where it works and where it does not

Running the business on one owner's mobile is common, and it works until it does not:

• One person, one device. A mobile number rings one handset. When the owner is on another call, driving or on holiday, the call goes to personal voicemail.
• Mixed personal and business calls. Customers keep the owner's personal number forever, and the number belongs to the owner's plan, which matters when the business is sold or the owner leaves. See whether to keep, port or replace a business number on a personal cell.
• No menu. Callers cannot choose sales or service, so every call interrupts the same person.

The usual fix is a business number that lives with a provider and rings mobiles in turn: staff keep their phones, the business keeps the number.

What households and customers actually use

Customers are mostly on mobiles. The US National Center for Health Statistics reports that in July to December 2025, 80.0% of adults lived in wireless-only households, up from 78.7% a year earlier, and 1.0% in landline-only households. (NCHS notes that the 2025 sample was smaller because data collection paused during the October to November 2025 federal shutdown.) These are household figures, not business figures, but they explain two things: customers expect to reach you from a mobile, and they expect to call you while you are away from a desk.

For businesses, copper is shrinking from the supply side too. Bell, for example, is shutting down business services on its copper network and moving customers to fibre. If you still have copper, read our guide to replacing copper phone lines before you get the notice.

Keeping your number when you switch

You do not have to choose your technology based on your number. The FCC states that if you stay in the same geographic area, you can keep your number when switching providers, and that this works between wireline, IP and wireless providers. It also says:

• simple ports must be processed in one business day under FCC rules;
• do not cancel your existing service before starting the new one;
• companies may charge to port, but the old company cannot refuse to port your number even if you owe a balance or a termination fee.

When moving from a landline to a mobile, the FCC adds that wireless 911 location and callback may be affected during the transition, and your wireline long distance company will not move with you. Canada has its own porting rules set by the CRTC; ask the new provider to confirm in writing that your specific number can be brought in.

Decision checklist

• How many people need to answer the main number? One: a mobile may do. Two or more: you need a system that rings several people.
• Does anything at your premises need a phone line in a power cut (alarm, elevator, fax)? Keep or replace that line deliberately.
• Is your internet reliable enough for desk phones, with a UPS and a failover?
• Where will staff be when calls come in: at desks, on the road, at home?
• Who owns the number, and is it on a business account?
• Do you need a menu so callers reach the right person?
• Have you compared total monthly prices with taxes and fees?

FAQ

Is VoIP better than a landline? For flexibility and features, usually yes: routing changes are software settings and calls can reach any phone. For working through a power cut with no preparation, a copper landline is better, but some carriers are retiring copper.

Can VoIP work in a power cut? Only if your modem, router and phones have backup power and the provider's network is up. A VoIP number that forwards to mobiles keeps reaching people whose phones have battery.

Does 911 work on VoIP? Interconnected VoIP providers must provide it in the US, and local VoIP providers must provide it in Canada, but location depends on the registered address and calls can fail during power or internet outages. Keep a mobile available.

Is a mobile enough for a business line? For a one-person business, often. Once two or more people share the calls, or you want to keep the number separate from a personal plan, a business number that rings several mobiles is easier to manage.

Can I move my landline number to VoIP or mobile? Yes, within the same geographic area, under portability rules in both countries. Do not cancel the old service first.

Auto Attendant gives a business a number with a simple menu that rings up to three team phones in turn for each option, at $29 USD per line per month.

Sources

1. VoIP and 911 Service - FCC Consumer Guide (last reviewed 12/27/2019); VoIP outages, E911 duties and limits; accessed 2026-10-28.
2. Voice over Internet Protocol (VoIP) - FCC Consumer Guide (PDF, last reviewed 12/30/19); what VoIP is, Universal Service Fund contribution; accessed 2026-10-28.
3. Tech Transitions: Network Upgrades That May Affect Your Service - FCC Consumer Guide (PDF, last reviewed September 22, 2025); copper line power versus fibre, cable and wireless backup power; accessed 2026-10-28.
4. 47 CFR 9.3 Definitions (interconnected VoIP service) - eCFR, up to date as of 10/27/2026; VoIP requires broadband and IP equipment; accessed 2026-10-28.
5. 9-1-1 Obligations of Local VoIP Service Providers in Canada - CRTC; 9-1-1 and customer notification duties, model notice (Telecom Decisions CRTC 2005-21 and 2005-61); accessed 2026-10-28, read via Internet Archive copy (capture 2026-03-09).
6. Copper network decommissioning - Bell Business; copper shutdown, 9-1-1 and alarm power on fibre; accessed 2026-10-28.
7. Wireless Substitution: Early Release of Estimates from the National Health Interview Survey, July-December 2025 - National Center for Health Statistics (released September 2026); wireless-only and landline-only household shares; accessed 2026-10-28.
8. Porting: Keeping Your Phone Number When You Change Providers - FCC Consumer Guide (last reviewed 12/10/2025); porting between wireline, IP and wireless; accessed 2026-10-28, read via Internet Archive copy.
9. Delete, Delete, Delete, FCC 25-80, 91 FR 1400 (14 January 2026) - Federal Register; 47 CFR 9.20 backup power rule sunset 1 September 2025, removed and reserved (effective 16 March 2026); eCFR version history of 9.20 confirms; accessed 2026-10-28.