If your business still has an AT&T landline, you may have received a letter saying your service will be discontinued. You may also have no idea how many copper lines you actually have, or what is plugged into them.
Here is the short answer: AT&T has federal approval to stop providing traditional copper phone service in parts of California on or after June 1, 2027, but California regulators and the courts are still fighting over whether that can happen. You do not need to panic. You do need an inventory. The businesses that will have the hardest time are not the ones with a single front-desk line. They are the ones with a forgotten fax line, alarm panel, or card terminal that quietly depends on copper.
On May 20, 2026, AT&T filed applications with the Federal Communications Commission to discontinue legacy copper voice service in parts of California. According to the California Public Utilities Commission (CPUC), AT&T says the affected areas include about 184,000 residential customers and 15,000 business customers, with service ending on or after June 1, 2027.
The affected business services are listed under names you may see on your bill: AT&T Business Individual Access Line Service, Measured Rate Business Service, or Business Local Exchange Access Line Service. If one of those names appears on your statement, this article applies to you.
The FCC’s public notice set June 29, 2026 as the date the applications would be automatically granted, and Broadband Breakfast reported that the FCC cleared them that day.
California has its own rules. The state designates AT&T as a “carrier of last resort,” which means it must offer basic phone service to anyone in its territory who asks for it. AT&T asked a federal court to block those rules while its lawsuit proceeds, and on July 16, 2026 a federal judge denied that request. AT&T responded that it was still proceeding with plans to stop selling traditional service to new customers.
In September 2026, the CPUC’s position was that AT&T can retire copper as long as the replacement service meets all of its carrier of last resort obligations, according to Law360’s case coverage. The California State Association of Counties has also stated that AT&T’s notices are not definitive.
Our take: For a business owner, the legal fight matters less than the direction of travel. Even if the June 2027 date moves, copper service is shrinking, and the CPUC itself raised concerns in July 2026 that prices for certain copper services had risen sharply. Waiting for the courts means making decisions under pressure later.
The CPUC published the full list of affected wire centers and an interactive map. Local wire centers on the list include Hollywood, Beverly Hills, Century City, Culver City, Glendale, Burbank-Palm, North Hollywood, Sherman Oaks, Van Nuys, Northridge, Newhall, and many Los Angeles central offices. Only portions of each wire center are included, so check the map or your AT&T notice rather than assuming.
Most owners think of “the phone line” as the number customers call. In many small offices, that number is only one of several copper lines, and the others were set up years ago by someone who no longer works there.
Devices that commonly rely on a traditional phone line include:
Public interest groups told the FCC years ago that many users still rely on landlines for alarm systems, medical monitoring, fax, and credit card machines. That has not changed. Most of these devices can work over modern connections, but each one needs to be checked, and some need a different adapter or communicator.
The following scenarios are illustrations, not real customer stories.
A Van Nuys auto repair shop has two AT&T lines on its bill. One rings at the front counter. The second turns out to serve a fax machine used for parts orders and a dial-up card terminal in the back office. The owner moves the main number to a cloud phone system, switches the parts supplier to email-to-fax, and asks the payment processor about an internet-connected terminal.
A Sherman Oaks dental office has a single main number, but the alarm company confirms the panel reports over a copper line. The office schedules the alarm company to install a cellular communicator before the phone cutover, so monitoring never lapses.
A Hollywood property management company discovers that the building’s elevator phone is on its own AT&T line billed to the owner. Because elevator phones are tied to building safety requirements, the company brings in its elevator service vendor to choose and test a replacement before changing anything.
In each case, the voice calls were the simplest part of the project.
Pull your last two AT&T bills and list every phone number and service name. Look for the business service names mentioned above. Many offices find lines they forgot existed.
Call each number, or have someone walk the office and trace phone cords back to devices. Write down what is connected: desk phone, fax, alarm, card terminal, elevator, gate. If a number rings nothing, it may still be connected to equipment that dials out only.
Use the CPUC map and read any AT&T notice carefully. Keep a copy of the notice with your inventory.
Business numbers can generally be transferred (ported) to a new provider. The order matters: start the transfer while the AT&T line is still active, and cancel AT&T only after the number is working on the new system. Canceling first can put the number at risk.
A copper line draws power from the phone company’s network, which is why landlines often work in a blackout. A VoIP system depends on your internet and your office’s power. The FCC’s backup power rules require providers to offer battery backup options for residential fixed voice service, so a business should not assume the same option applies to its lines. Practical safeguards include:
Ask any provider how your business address is registered for emergency calls, and update it if staff work from more than one location.
Move the main number first, test inbound and outbound calls, then handle fax and devices one at a time. Test alarms with the monitoring company on the line.
Costs depend on how many users you have and what equipment needs replacing. A cloud phone system is usually priced per user per month, while alarm communicators, fax adapters, and new card terminals may carry one-time charges from those vendors.
Watch for these limitations:
The technology here is mature. The hard part is discovery and coordination: tracing lines, talking to the alarm company, scheduling the port, and making sure nobody loses a call on cutover day. A provider that handles setup with you, instead of handing you a login, reduces the chance of something being missed.
Supreme Call is a business VoIP provider serving Los Angeles and the San Fernando Valley. Its plans include free number porting, online fax, and a mobile app, and a Supreme Call specialist handles configuration, phone provisioning, and team training. For businesses that want to keep a physical fax machine, Supreme Call supports fax-enabled adapters as well as email-to-fax. Its feature list also includes automatic service failover, which switches to a 4G or other network when your main internet connection goes down.
Supreme Call does not replace your alarm company, elevator vendor, or payment processor, but it can help you plan the voice and fax side of the move around them.
If you have an AT&T notice or are not sure what your copper lines are doing, book a one-on-one call with Supreme Call to review your setup before you need to make a rushed decision.
AT&T has FCC approval to discontinue copper landline service in portions of 360 California wire centers on or after June 1, 2027, affecting about 15,000 business customers by AT&T’s estimate. However, California’s carrier of last resort rules remain in effect while AT&T’s lawsuit continues, and the CPUC says AT&T may retire copper only if replacement service meets those obligations. The final timing is uncertain.
Your business line may be affected if it is a traditional AT&T copper service, such as Business Individual Access Line Service or Measured Rate Business Service, located in one of the listed wire centers. Check your bill for those service names, read any notice from AT&T, and compare your address against the California Public Utilities Commission’s published map of affected areas.
Yes, business phone numbers can generally be transferred to a new provider through a process called porting. Start the port while your AT&T line is still active, and cancel AT&T service only after the number is confirmed working on the new system. Canceling the old line first can cause the number to be released and become difficult or impossible to recover.
A fax machine can usually keep working after a switch from copper, either through a fax-enabled adapter that connects the machine to an internet phone service or by moving to online fax that sends and receives documents by email or app. Physical fax machines can be sensitive to internet connection quality, so online fax is often the more reliable option for regular use.
An alarm system that reports to a monitoring center over a copper line may stop communicating when that line is discontinued. Contact your alarm company before changing any phone service. Many alarm providers offer cellular or internet communicators as replacements. Schedule the alarm upgrade first, then test the panel with the monitoring center after the change.
A VoIP phone system does not work during a power outage unless your internet equipment and phones have backup power. Unlike copper lines, VoIP depends on your office’s electricity and internet connection. Battery backups for networking equipment, a cellular backup internet connection, and forwarding calls to staff mobile phones are common ways to keep a business reachable.
Waiting is a risk, because the migration work takes time even if the June 2027 date changes. Inventorying lines, coordinating with alarm and equipment vendors, and porting numbers can take weeks. Starting the inventory now costs little and lets you move on your own schedule instead of reacting to a short deadline or rising copper service prices.
No, copper retirement is happening nationwide. AT&T has received federal approval to retire copper in large parts of its footprint outside California and has said it plans to retire most of that copper by the end of 2029. California has received extra attention because its carrier of last resort rules are being challenged in court and at the FCC.
