ATDS (Automatic Telephone Dialing System)

The TCPA's term for autodialers — equipment whose use triggers stricter consent requirements.

An Automatic Telephone Dialing System (ATDS) is, under the TCPA, equipment "with the capacity to store or produce telephone numbers to be called, using a random or sequential number generator, and to dial such numbers." Using an ATDS to call a consumer's cell phone without Prior Express Written Consent (PEWC) is a TCPA violation.

The 2021 Facebook v. Duguid decision

The Supreme Court's 2021 decision in Facebook v. Duguid narrowed the ATDS definition significantly. The Court held that equipment qualifies as an ATDS only if it uses a random or sequential number generator — predictive dialers that work from preloaded lists were largely excluded. This narrowed the universe of equipment that triggers strict TCPA consent requirements.

What still counts as ATDS

• Equipment that generates random or sequential numbers automatically.
• Some hybrid systems where number generation occurs as part of dialing.
• Robodialing equipment using prerecorded or artificial voice (separate prohibition under the TCPA).

What it means for operators

Predictive dialers and click-to-dial systems that work from human-curated lead lists are mostly not ATDS post-Duguid. But the TCPA still prohibits prerecorded calls to cell phones without consent regardless of ATDS status. State laws (CA, FL, others) also impose their own definitions that may capture broader equipment.