What Is an Autodialer? The TCPA ATDS Definition After Duguid

TCPA Autodialer Definition: What the Statute Says

The TCPA defines an “automatic telephone dialing system,” often called an ATDS or autodialer, in 47 U.S.C. 227(a)(1). It is equipment “which has the capacity (A) to store or produce telephone numbers to be called, using a random or sequential number generator; and (B) to dial such numbers.” The FCC’s rule repeats the same definition at 47 CFR 64.1200(f)(2).

This definition matters because the TCPA’s best-known ban depends on it. Section 227(b)(1)(A) prohibits calls to cell phones “using any automatic telephone dialing system or an artificial or prerecorded voice” without prior express consent. If a live person placed the call from equipment that is not an ATDS, and no recording played, that ban does not apply.

Facebook v. Duguid Explained: How the Supreme Court Narrowed the ATDS Definition

For years, courts disagreed about the phrase “using a random or sequential number generator.” Some read it as modifying both “store” and “produce.” Others read it as modifying only “produce.” Under the broader reading, any system that stored a list of numbers and dialed them automatically could count.

The Supreme Court settled the question on April 1, 2021. In a unanimous decision in Facebook, Inc. v. Duguid, Justice Sotomayor wrote:

“To qualify as an ‘automatic telephone dialing system,’ a device must have the capacity either to store a telephone number using a random or sequential generator or to produce a telephone number using a random or sequential number generator.”

The facts show how narrow the definition now is. Noah Duguid never had a Facebook account and never gave Facebook his phone number. Even so, he received login notification texts from Facebook. Facebook’s system sent those alerts to numbers stored with user accounts. It did not generate numbers at random or in sequence, so it was not an autodialer, even though the texts were sent to a stranger. The Court acknowledged the policy concerns Duguid raised, but it said his disagreement was with the wording Congress chose, and the statute’s text controlled.

Duguid Footnote 7: The Stored-List Question Courts Still Debate

One footnote in the opinion, footnote 7, left a door open. It described a device that uses a random number generator to determine the order in which to pick numbers from a preexisting list, then stores them to be dialed later. That kind of system could fall within the definition. Lower courts are still working out how far the footnote reaches, and results vary from court to court.

What Is Not an Autodialer After Duguid

Courts have generally found that the following are not autodialers:

• A dialer that calls a customer list uploaded from a spreadsheet, in the order the list is sorted.
• A texting platform that sends a message to everyone who signed up on a website.
• A “click to dial” system where an agent clicks each number.
• A predictive dialer that pulls numbers from a stored list of leads. The exception is a dialer that includes a random or sequential number-generation feature.

A company that only calls numbers from its own records is usually outside the ATDS definition under Duguid, regardless of how many calls it places.

What May Still Count as an Autodialer Under the TCPA

• Number-generating systems. Equipment that generates the numbers it dials, randomly or sequentially.
• Footnote 7 systems. Equipment that uses a random or sequential number generator to store numbers for later dialing.
• Calls with no prior relationship. Campaigns where the caller clearly did not get your number from any relationship with you. That fact alone does not prove an ATDS, since Duguid itself involved texts to a stranger. Combined with other facts, though, it can support an argument that the numbers were generated rather than pulled from a customer list. It can also justify requesting records of the equipment.

Robocall and Telemarketing Claims That Don’t Require an Autodialer

This is the part most people miss. Duguid narrowed one piece of the TCPA and left the rest alone.

Courts do not all agree on whether every claim in this table can be brought by a private person. The calling-hours and company-specific Do Not Call claims draw the most disagreement. It is worth checking how courts in your area have ruled.

If the call played a recording or an AI voice at any point, you generally do not have to prove anything about the dialer. The FCC’s 2020 “soundboard” ruling, which it reaffirmed in its 2024 AI ruling, says a live agent choosing which prerecorded clips to play “does not negate the clear statutory prohibition against initiating a call using a prerecorded or artificial voice.”

Since a 2025 Supreme Court decision, federal courts are no longer required to follow FCC interpretations like these. Courts can still find them persuasive, and many do, but the FCC rulings are no longer automatically binding in a private lawsuit. See our prerecorded and AI voice call page.

Where the TCPA Autodialer Ban Applies: Cell Phones vs. Landlines

The statute does not ban autodialed calls everywhere.

• Protected lines. Section 227(b)(1)(A) bars non-emergency autodialed calls made without consent to:
  • emergency lines,
  • hospital and nursing home patient rooms, and
  • cell phones and other numbers where the called party pays for the call.
• Home landlines. The separate ban in 227(b)(1)(B) covers only artificial or prerecorded voice calls. An autodialed call to a home landline with a live agent on the line is not barred by 227(b) at all. For landlines, the Do Not Call rules and the prerecorded-voice rule do most of the work.
• Multi-line businesses. One more autodialer rule protects businesses. It is unlawful “to use an automatic telephone dialing system in such a way that two or more telephone lines of a multi-line business are engaged simultaneously” (227(b)(1)(D); 64.1200(a)(5)).

Equipment “Capacity” and the ATDS Test

The definition also turns on the word “capacity.” The statute asks what the equipment “has the capacity” to do, and Duguid framed its holding the same way. A device must be capable of storing or generating numbers using a random or sequential number generator.

How much weight that word carries is still open. One example is software that could be configured to generate numbers but was never used that way. Lower courts continue to sort out questions like this.

Autodialed Text Messages and the TCPA

The ATDS question often comes up in marketing texts. Section 227(b) applies to texts only if they were sent with an autodialer, because texts have no “voice.” Mass texting platforms often send to stored lists, and senders cite Duguid to argue they are not autodialers.

Text claims that do not depend on the dialer face a separate problem. These include texting after a STOP reply and texting a number on the Registry. In its July 2026 Steidinger ruling, the Seventh Circuit held that texts are not “telephone calls” under the TCPA’s Do Not Call private right of action. That ruling binds courts only in Illinois, Indiana, and Wisconsin. Other courts have reached the opposite conclusion, so where you live can affect whether a text claim survives. Our text message rules page covers both issues.

State Autodialer Laws: When State Mini-TCPA Rules Go Further

The federal ATDS definition is not the last word. Duguid interpreted only the federal statute. State telemarketing laws use their own wording, and state courts read that wording on its own terms.

Florida’s Telephone Solicitation Act is one example. It gives a private right of action with $500 minimum damages per violation, trebled if the violation was willful or knowing (Fla. Stat. 501.059(10)). Florida amended the law to cover only systems that both select and dial numbers, so the state definition is narrower than it once was. Even so, the FTSA expressly reaches text messages, which can matter where federal text claims are limited.

Whether a particular dialer is covered depends on each state’s own wording and how its courts read it. Check our state autodialer law pages for your state’s rules before assuming a federal dismissal ends the case.

How to Tell If an Autodialer Called You

You usually cannot identify the equipment from your end. These signs help build the record:

• A pause or click before anyone speaks, or a dead line when you answer.
• A recording, or a voice that sounds synthetic or does not respond naturally to questions.
• Calls to a number you never gave anyone, or to a brand-new number.
• Many calls from different numbers are selling the same thing.
• Texts that address you by the wrong name, or by no name.

Write these details down after each call. Our evidence call log has fields for them.

Next Steps If You’re Getting Robocalls or Spam Texts

• If the calls used a recording or an AI voice, the autodialer question may not be relevant to your case.
• If they were live calls or texts, focus on the Do Not Call rules and on whether you told the caller to stop.

Either way, gather dates, numbers, and caller names now, because deadlines can apply to these claims. Read our guide to suing a telemarketer to see how equipment questions come up in discovery.

TCPA Autodialer FAQ+

What is an autodialer under the TCPA?

It is equipped with the capacity to store or produce telephone numbers using a random or sequential number generator, and to dial them (47 U.S.C. 227(a)(1)). After Facebook v. Duguid (2021), a random or sequential number generator must be used to generate or store the numbers.

Is a predictive dialer an autodialer after Duguid?

Usually not, if it only dials numbers from a stored list. It may qualify if it uses a random or sequential number generator to produce or store the numbers it dials.

Can I still sue for robocalls if the company didn’t use an autodialer?

Often, yes. Claims can still exist if the call used a prerecorded or artificial voice, violated the Do Not Call rules, or continued after you told the company to stop. Those claims do not depend on the ATDS definition. Some, especially text-based claims, depend on where you file.

Do state autodialer laws follow Duguid?

Not necessarily. Duguid interpreted the federal statute. States with their own telemarketing laws define covered equipment in their own words.