POTS line replacement: the complete guide for buildings

Who this page is for

• You manage one or more buildings with elevator phones, fire alarm panels or call boxes that still run on copper phone lines.
• You received a carrier notice about discontinued service or a big price increase, or you expect one.
• Your phone bill lists lines and nobody can tell you what each one connects to.
• You need to explain the options and a budget to an owner, a board or a district.

What a POTS line is and why yours is at risk

POTS stands for plain old telephone service. It is an analog line on a copper pair from the phone company’s central office, and the central office powers it, so it keeps working when your building loses power.

That self-powered, always-on design is why elevator phones, fire alarm dialers, burglar alarms and fax machines were built around POTS. The devices expect dial tone, ring voltage and clean analog tones.

The carriers that own those copper networks are retiring them. On December 1, 2025, AT&T filed an application with the FCC to discontinue legacy voice service for about 90,000 customers in parts of 18 states. The filing says service ends on or after November 15, 2026, pending approval.

AT&T has also said it is working to exit legacy copper operations across the large majority of its wireline footprint by the end of 2029, in its December 2024 investor release.

The federal rules changed too. In March 2026 the FCC adopted FCC 26-19, which gives every discontinuance application a 31-day automatic grant period and lets carriers qualify for streamlined review by showing that one of five replacement services is available. The details, the California exception and what to do with a notice are in my AT&T copper retirement guide.

What each line in your building needs

A replacement plan fails when it treats every line the same. Each device uses the line differently, and each one has a different person who signs off.

Line type	What the device does on the line	What the replacement must handle	Who confirms it	Details
Elevator emergency phone	Dials out when a passenger presses the button; voice both ways	Line monitoring, battery backup, routing to a 24/7 answering point	Elevator inspector (state or city)	Elevator phone lines
Fire alarm panel (DACT)	Sends coded data tones to a supervising station	Alarm data formats, two paths or an approved single path, listed equipment	Fire marshal or other AHJ, plus the monitoring company	Fire alarm communicators
Burglar or security alarm	Sends coded tones to a central station	Alarm data formats such as Contact ID, battery	Alarm company, sometimes the insurer	POTS in a box
Emergency call box, area of refuge, pool phone	Voice to a monitored point, often hands-free	Auto-dial, location ID, battery	Building official or fire department	Emergency call boxes
Gate or door entry	Calls a resident or guard and receives a tone to open	Inbound and outbound calls, DTMF tones	Property manager, gate vendor	POTS in a box
Fax machine	Sends pages as modem tones	Fax over cellular or T.38, often at lower speed	Your compliance lead (for example in healthcare)	POTS in a box
ATM or card terminal	Dials a processor with a modem	Modem support, PCI requirements	The bank or processor	POTS in a box
Modems (meters, elevator monitoring, SCADA)	Dial-up data	Modem passthrough	Equipment vendor	POTS in a box
Main business or school line	Voice calls, sometimes through a PBX	Number porting, 911 location data	IT or telecom lead	Schools and districts

If you are not sure what a line connects to, start with the inventory steps on my property manager page. Terms such as DACT, AHJ and supervising station are defined in the glossary.

Three ways to replace a POTS line

1. POTS in a box (managed cellular gateway)

A POTS-in-a-box unit is a small router with LTE, analog phone ports and a battery. Your devices plug into it as if it were the phone company’s jack, and the provider manages the cellular service, the phone service and the monitoring as one package.

This is the approach most building portfolios use, because one box can serve several line types in the same room. I explain components, battery and the weak spots in POTS in a box explained.

2. Dedicated cellular communicators

A dedicated communicator is built for one job. Fire alarm communicators connect to the panel and send signals over cellular (and sometimes internet) straight to the monitoring company. Cellular elevator phones do the same for the cab.

These are usually sold and installed by your alarm or elevator company. They are often the cleanest answer for a fire alarm panel, because the equipment and the monitoring account are listed and supported together.

3. VoIP adapters on your internet connection

An analog telephone adapter (ATA) turns a phone line into a VoIP line on your internet service. It is the cheapest way to keep a basic phone working.

It is also the riskiest for life-safety lines. Regular VoIP compresses audio, which can break alarm tones and fax, and it fails when the internet or the building’s power fails. The Minnesota State Fire Marshal says VoIP is “not recommended for transmitting fire alarm signals.”

Approach	Best for	Typical power backup	Main risk
POTS in a box	Mixed lines in one room: elevator, alarm, fax, gate	Vendor batteries rated from 8 to 48 hours, depending on model and options	Weak cellular signal in basements and machine rooms
Dedicated communicator	Fire alarm panels, single elevator phones	Runs from the fire panel or a listed power supply	One more vendor contract per system
VoIP adapter	Low-risk voice lines, office phones	Only if you add a UPS for the modem and adapter	Alarm, fax and modem failures; outage when internet drops

What the codes say, in short

These are summaries. The adopted edition, local amendments and the official who signs off decide your case.

• Elevators. ASME A17.1 Section 2.27.1 covers car emergency communication. In the 2016 edition, Washington’s elevator program summarizes it as two-way communication to a location staffed by authorized personnel, with the line monitored and a handset not allowed in the car (TC 18-04). Later editions add visual and text communication. More on elevator phone requirements.
• Fire alarms. NFPA 72 Chapter 26 sets how signals reach a supervising station. A DACT has historically needed two phone lines or one line plus another path. Newer editions allow other technologies, including single-path systems that meet conditions. Details on the fire alarm communicator page.
• Areas of refuge and elevator landings. The International Building Code requires two-way communication at elevator landings on accessible floors above or below the exit level, with exceptions, according to the ICC’s 2018 IBC summary. See emergency call boxes and areas of refuge.
• 911 from phone systems. Kari’s Law and RAY BAUM’S Act set direct 911 dialing, notification and dispatchable location rules for multi-line telephone systems, per the FCC. This matters most when you replace a PBX or main lines, as in schools and districts.

POTS replacement options compared

Prices below are only what each provider publishes. Where a provider publishes nothing, I say so. Claims about listings are the provider’s own statements.

Option	Best for	How it works	Pricing info (as of October 2026)	Pros	Cons
Ooma AirDial	Mixed lines in commercial buildings	LTE plus wired Ethernet at the same time (“MultiPath”); 4 analog ports per unit per its datasheet	No published price; quote only (Ooma)	Ooma says it is UL 864 certified and has a California State Fire Marshal listing	16 hours of standby battery unless you add the external battery
Granite EPIK	Multi-site companies with many line types	Edge device with dual-SIM LTE and wired failover; up to 8 analog lines	No published price (Granite)	Supports modems and high-volume fax per Granite; FDNY approval announced	Granite notes some jurisdictions may require wireline for fire and life safety
IPFone POTSBOX Pro	Small to mid portfolios	2, 4 or 8 port adapters in a telco enclosure; dual SIM	No published price (IPFone)	Up to 16 lines; 12 to 48 hours battery per IPFone	No UL or fire marshal listing named on its product page
BCN POTS over LTE	Retail and multi-site accounts	Dual-SIM LTE with optional wired second path	No published price (BCN)	Bundles voice, data and security billing	Standard battery 8 hours, 24 hours optional
MetTel POTS Transformation	Large enterprises and government	Multi-WAN device, dual-SIM LTE/5G, up to 8 lines	No published price (MetTel)	Up to 48 hours battery per MetTel; supports modems and POS	Aimed at large enterprise and government accounts
AT&T Phone for Business - Advanced (now AT&T Business Voice)	AT&T customers with simple voice or fax lines	AT&T device on AT&T’s LTE network	$99.99 per month before taxes and fees, including an AT&T-owned device, per AT&T’s May 2026 FCC filing	Offered by the carrier that sent the notice	Single carrier; AT&T’s notices do not mention elevator or fire alarm use
Napco StarLink Fire Max 2	Fire alarm panels	Dedicated fire communicator, Verizon and AT&T	Sold through alarm dealers; no public price (Napco)	Napco says it is UL 864 listed, with single and dual path plans	Fire only; needs a monitoring account
Kings III	Elevator and emergency phones	Cellular elevator phone plus its own 24/7 dispatch center	No published price (Kings III)	Equipment, installation, maintenance and monitoring in one service	Elevator and emergency phones only

I don’t work with Kings III, Napco or AT&T’s direct offer, but each is a good fit in the situation described. How the providers I work with pay me is explained on How I get paid.

What POTS replacement costs

Here are the only hard numbers I found from official sources:

• AT&T’s December 2025 FCC application lists AT&T Phone - Advanced for business at $99.99 per month before taxes and fees, with an AT&T-owned device included.
• The same application says the listed rate for AT&T’s legacy business line averages about $1,700 per month, while most customers pay an effective rate under $200 per month after discounts.
• AT&T’s May 2026 California application gives a guidebook rate of about $2,700 per month in most covered wire centers, before discounts, for the same type of business line.
• AT&T’s consumer page lists AT&T Phone - Advanced at $45.00 per month plus taxes and fees, as of October 2026 (AT&T).

Ooma, Granite, IPFone, BCN and MetTel do not publish per-line prices. What changes a quote:

• Lines per device. A 4-port or 8-port unit spreads the device and data cost across lines.
• Monitoring. Elevator answering services and fire alarm monitoring are often billed separately from the line.
• Hardware. Rental is folded into the monthly fee; purchase raises the one-time cost.
• Installation. The elevator or alarm contractor may need to be on site, and that visit is billed by them.
• Signal. An external antenna or a second carrier adds cost in basements and shafts.
• Contract length. Longer terms usually lower the monthly rate and raise the exit cost.

Plug your bill and a written quote into the POTS cost calculator to see the monthly difference and the break-even month.

A rollout plan for a building portfolio

1. Inventory every line (week 1 to 3). Match each number on the bill to a device and a room. The property manager checklist shows how.
2. Sort by risk and deadline (week 2 to 4). Lines named in a carrier notice and life-safety lines go first.
3. Cancel what nobody uses. Dead lines are pure savings and need no replacement.
4. Test signal on site. Elevator machine rooms and basement telecom rooms are where cellular fails.
5. Get two written quotes per line type. Compare monthly cost, one-time cost, battery, monitoring and contract terms.
6. Book the trades. The elevator contractor reprograms and tests the cab phone; the alarm contractor connects and tests the panel with the monitoring company.
7. Pilot one building, then roll out. Keep the copper line active until the new path passes testing and any required inspection.

My recommendation by scenario

• If you have 1 to 3 lines in one building: a POTS-in-a-box unit usually covers the elevator phone and an alarm line together. For a fire alarm panel, ask your alarm company first whether a dedicated communicator is simpler for the AHJ.
• If you manage 5 to 20 buildings: standardize on one gateway provider for elevator, gate and fax lines, with one portal for alerts. Let each building’s alarm company quote the fire panel separately, then compare.
• If you manage 20 or more sites in several states: run a pilot in your toughest building (deep basement, old panel) before signing a portfolio contract, and get per-site pricing in writing.
• If a line only serves a fax or a card terminal: check whether the department still needs it. Many can move to e-fax or an IP terminal instead.

Questions to ask any provider

• Which of my line types do you support, and which do you not support?
• Is the equipment listed or certified for fire alarm use, and can you send the listing document?
• How long does the battery last on standby and in use, and can it be extended?
• Which cellular carriers does the device use, and does it switch carriers automatically?
• Who receives the alert when a line, battery or signal fails?
• Who installs, and do you coordinate with my elevator and alarm contractors?
• What is the contract term, and what does it cost to cancel early or remove a line?

Common mistakes

1. Replacing lines before inventorying them. You pay to replace dead lines and miss the one that serves the elevator.
2. Assuming every device works on regular VoIP. Alarm tones, fax and modems are where cheap adapters fail.
3. Skipping the fire marshal or inspector. A new communication path on a fire alarm or elevator can need review or a permit.
4. Ignoring battery time. A box rated for 8 hours does not match a requirement that expects 24 hours.
5. Testing signal from the parking lot. Test where the device will be mounted.
6. Cancelling copper before acceptance testing. Keep the old line until the new one passes end-to-end tests.

When you have your line count and the notice in hand, send me your building details for a POTS replacement quote.