4 Building Systems Still Running on Old Copper Phone Lines

Walk into the utility closet of almost any office building, retail store or medical practice and you will probably find a bundle of old copper phone wires.

Your team stopped using them years ago. Calls run on cell phones, laptops and a cloud phone system. But the copper lines are still on the bill, because a few quiet machines depend on them: the fire alarm panel, the elevator emergency phone, the security system and the fax machine.

Most owners assume those lines will keep working as long as the bill is paid. That assumption is getting harder to rely on.

AT&T is federally authorized to begin discontinuing its copper phone service, often called POTS ("plain old telephone service"), on or after November 15, 2026, in parts of wire centers across 18 states. The company told the FCC that service reaches about 90,000 customers, and it plans to exit copper across most of its footprint by the end of 2029. Verizon is retiring legacy switching equipment as well, including sites in New York.

New York isn't on AT&T's November list. But if your business has locations in other states, or simply still pays for copper lines, now is the time to plan the replacement on your schedule rather than the carrier's.

Why carriers are retiring copper

Copper networks are decades old and costly to maintain. Carriers would rather invest in fiber and wireless, and federal regulators have made the switch easier.

In March 2025, the FCC eased several rules for retiring copper and discontinuing legacy service. In March 2026, it went further, streamlining discontinuance approvals and cutting some disclosure filings. AT&T says copper service has already ended in more than 500 communities.

At the same time, prices for remaining copper lines have been climbing. North Carolina's state IT department, for example, published a sample AT&T tariff rate for a business line far above its contract rate, warning agencies to plan their migration.

The 4 systems that still depend on copper

Most businesses don't realize they still have copper lines until something stops working. Check these four first:

• Fire alarm panels. Many panels still send alarm signals to the monitoring center over a copper line. A dead line can mean a trouble signal and a failed inspection.
• Elevator emergency phones. The emergency button in the car needs a working line. The elevator code (ASME A17.1) also calls for at least 4 hours of backup power for that communication.
• Security panels, door buzzers and gate intercoms. Burglar alarms and parking gates often dial out over an analog line.
• Fax machines and older card terminals. Medical offices, pharmacies and retail counters still use analog lines for faxes and some payment terminals.

Why a basic internet phone adapter is the wrong fix

When owners hear copper is going away, a common shortcut is to plug the alarm or elevator phone into a cheap internet phone adapter. For life-safety equipment, that's risky.

A basic adapter stops working when the building loses power or the internet goes down. And fax signals often don't survive the compression used in standard internet calling; Cisco's own troubleshooting guide notes that fax transmissions "usually do not correctly pass through" compressed voice codecs. Alarm panels use similar tone-based signaling, which is why alarm companies are cautious about it.

What a purpose-built replacement looks like

Copper replacement devices built for alarms and elevators work differently:

• Same jack, new connection. The device has a standard analog phone port, so the existing panel, elevator phone or fax plugs straight in.
• Cellular, often with a second path. Many connect over cellular networks, and some use two carriers or add a wired internet connection as a backup.
• Backup power. A built-in battery keeps the line working during an outage. Fire alarm communicators generally need 24 hours of standby power under NFPA 72, and elevator phones need at least 4 hours.
• Code acceptance. NFPA 72 permits cellular communicators, but your local fire authority has the final say. In New York City, that means the FDNY's requirements, so loop in your alarm company before you switch.

Lines that are simply phone lines, such as a front desk or a back-office number, can usually move to a cloud phone system instead, which often costs less than the copper line it replaces.

Replacing copper lines without rewiring

Take inventory first

Pull your last few phone bills and list every analog line, its number and what it's connected to. Bills often include lines nobody can identify; our year-end telecom contract audit covers how to find them.

Move numbers before a disconnect date

If you wait for the carrier to disconnect a line, you risk losing the number programmed into your alarm panel or posted in the elevator. FCC rules require simple single-line transfers to finish in one business day, but multi-line business transfers usually take at least four business days, and large projects can take up to about three weeks. Start early.

Line up approvals and testing

Schedule your alarm and elevator contractors to test each device after it is installed, and keep the paperwork for your next inspection.

Check your connectivity

If a device will use your office internet as a backup path, make sure that connection is reliable. Our business internet page covers fiber, cable and wireless backup options.

Check the utility closet before the carrier does

Copper retirement is moving faster each year, and the businesses that plan ahead avoid emergency installs, failed inspections and lost numbers. A short inventory today tells you exactly which lines matter and what they should move to.

Cambia Digital can review your phone bills and building lines, identify which ones support life-safety equipment, and compare replacement options side by side, with no vendor bias.

Sources

• FCC: Public Notice DA 25-1042 on AT&T discontinuance applications (December 12, 2025)
• AT&T Section 214 discontinuance application, courtesy copy filed with the Florida PSC (December 2025)
• Broadband Breakfast: AT&T Approved to Discontinue Service at More Than 30% of Copper Footprint This Year (January 13, 2026)
• AT&T: Delivering Faster, More Reliable Connections – And Simplifying Our Network Along the Way (October 19, 2026)
• Broadband Breakfast: FCC Loosens Copper Retirement Rules (March 20, 2025)
• FCC: FCC Takes Action to Speed Up Rollout of Modern, High-Speed Networks (March 26, 2026)
• Verizon: Network Disclosures 2025–2026
• North Carolina Department of Information Technology: AT&T Sample Tariff Rates
• North Carolina Department of Administration: POTS Copper Telephone Line Replacement Service Requirements (2023)
• FCC: Porting: Keeping Your Phone Number When You Change Providers
• FCC: LNPA Working Group Best Practices (number porting intervals)
• Cisco: Troubleshoot Fax Relay