Auto dialer software: the types, the law and how to choose

What an auto dialer automates (and what it does not)

An outbound call has five parts: pick the next contact, dial, wait through the ring, handle the outcome (person, voicemail, dead number), and log it. Dialing by hand, a rep does all five. Each type of auto dialer takes over a different set of them.

The row that matters most is waiting through the ring. On cold lists most dials are not answered, so ring time is usually the largest block of a rep's hour. Only the multi-line types (parallel and predictive) take it off the rep, and they pay for it with a harder job at the moment someone says hello.

The five types of auto dialer, explained

1. Preview dialer

Shows the rep the next record, then dials when the rep clicks. Slowest, best prepared. Right for strategic accounts where research changes what you say. Definition: preview dialer.

2. Power (progressive) dialer

Dials the next number automatically as soon as the rep finishes the last call, one call at a time. No connect delay and no abandoned calls. The full explainer is what a power dialer is.

3. Parallel (multi-line) dialer

Rings several numbers at once for one rep, detects which one a human answers, connects the rep to that call and ends the others. Built for SDR teams cold-calling direct dials and mobiles, where most calls go unanswered. Definition: parallel dialer.

4. Predictive dialer

Dials a pool of numbers across many agents, using a pacing algorithm that predicts when agents will be free. Common in large consumer contact centers. When more people answer than agents are free, calls are abandoned, which is why abandonment is capped by regulation (see the law section). Definition: predictive dialer.

5. Voice broadcast and AI voice agents

Some tools sold as auto dialers play a recorded message or put an AI voice on the call instead of a person. These are a different category with the strictest rules: the TCPA restricts calls using an artificial or prerecorded voice, and the FCC has ruled that AI-generated voices are "artificial". For how AI fits into human-led outbound, see what an AI SDR is.

How many lines? The math most comparisons skip

Vendors compete on line counts. The right number depends on your connect rate, because every extra line raises two things at once: the chance that someone answers this round, and the chance that two people answer and one gets dropped. Here is a simple model. The inputs are illustrative assumptions, not benchmarks.

• Connect rate per dial: 5% (each number independently).
• A round of calls rings for 25 seconds, plus 10 seconds to disposition and start the next round.
• When a person answers, the conversation plus notes takes 4 minutes. The other lines in that round end.
• Power dialing is the 1-line case.

The chance at least one of N lines connects is 1 - 0.95^N. Expected seconds per round is 35 + that chance x 240. Rounds per hour is 3,600 divided by that. Dropped live answers are the extra people who picked up in a round where someone else was already connected.

Three things fall out of this. Conversations rise steeply from 1 to 3 lines, then flatten, because once the rep is busy talking most of the hour, more lines cannot add much. Dropped answers grow faster than conversations. And the shape depends heavily on connect rate: at 10%, 8 lines drops nearly 5 live answers an hour in the same model, while at 3% it drops about 1. High line counts suit low-connect lists; warm lists want fewer lines.

Cloud-based vs on-premise auto dialers

Almost every sales auto dialer bought today is cloud-based: it runs in a browser or desktop app, uses the vendor's telephony, and connects to your CRM over its API. On-premise dialers (software and telephony hardware you host) survive mainly in large contact centers with legacy phone systems or strict data-residency rules.

B2B vs B2C auto dialers: different products for different jobs

Search results mix sales dialers with contact-center dialers, which is why so many "best auto dialer" lists feel random. They solve different problems.

If you run outbound sales, shortlist sales dialers (best sales dialers, best power dialers, best parallel dialers), not contact-center suites.

Auto dialers and the law: TCPA, consent and the TSR

"Auto dialer" vs "automatic telephone dialing system"

The TCPA restricts calls made with an "automatic telephone dialing system" (ATDS) to cell phones and certain other lines without prior express consent. In Facebook v. Duguid (2021) the Supreme Court held that a device qualifies only if it can store or produce numbers "using a random or sequential number generator." Most sales dialers call numbers from a list you provide, which is a different design. But the Court was explicit that its ruling does not affect the separate ban on artificial or prerecorded voice calls.

Prerecorded and AI voices need consent

• The FCC's rules (47 CFR 64.1200) restrict calls using an artificial or prerecorded voice to cell phones without prior express consent, and require prior express written consent for prerecorded telemarketing calls to homes and mobiles.
• The FCC's consumer guide states that "AI-generated voice calls are illegal unless the consumer has agreed to receive them or the caller is exempt."
• The FCC has ruled that ringless voicemail to wireless phones is a call that needs consent. Ask your counsel how recorded voicemail drops to mobiles fit your consent records.

Abandoned calls: the rule that shapes predictive and parallel dialing

Under both the FCC rules and the FTC's Telemarketing Sales Rule, a telemarketing call is "abandoned" if the person is not connected to a live sales rep within two seconds of their completed greeting. Abandonment is capped at 3% of calls answered by a live person, measured per campaign over each 30-day period, and abandoned calls must play an identification and opt-out message. These rules are written for telemarketing to consumers, but they explain why connect speed and dropped answers matter on any multi-line dialer.

B2B exemptions, and their limits

• The FTC says most business-to-business calls are exempt from the TSR, except calls selling nondurable office or cleaning supplies and calls to a business line pitching an employee something for personal use (FTC).
• The TCPA's restrictions on prerecorded and artificial voice calls to cell phones do not depend on whether the person is a consumer or a buyer at a company. A mobile number is a mobile number.
• States add their own rules. Florida's Telephone Solicitation Act, for example, requires prior express written consent for unsolicited sales calls that use "an automated system for the selection and dialing of telephone numbers" or a recorded message (Fla. Stat. 501.059). It is written around consumer goods and services, but its wording is broader than the federal ATDS definition.
• Do Not Call: telemarketers to consumers must scrub against the National Do Not Call Registry and honor every do-not-call request. Whatever your call type, keep an internal do-not-call list and honor it.

Auto dialer buying checklist

Take this into every demo. The first six questions eliminate most mismatches before you ever discuss price.

1. Which modes, and how many lines per rep? Can you set lines per list or per rep, and drop to single-line power dialing when a list is warm?
2. What happens when two people answer at once? And how fast is the rep connected after a human says hello?
3. Native CRM integration for my CRM? Does it read lists live and write calls, outcomes and recordings back as activities? (See HubSpot, Salesforce, Close.)
4. How are bad numbers handled? Are numbers checked before dialing, or do reps discover them on the ring? See phone number validation.
5. How do you keep caller IDs from being labeled spam? Monitoring, remediation, registration, and whether it costs extra. See spam likely and STIR/SHAKEN.
6. What happens when an AI call screener answers? iPhone and Android assistants now pick up many unknown calls; does the dialer hang up, hold, or respond? See AI call screening.
7. Compliance controls: internal DNC list, calling-hour windows by time zone, recording-consent handling, voicemail-drop settings.
8. Seat minimum and contract length. Orum's pricing page states a 9-seat minimum; others sell monthly per seat. A small team should not pay for empty seats.
9. All-in cost per rep per month, including numbers, spam protection, transcription and coaching add-ons.
10. Reporting: dials, connects, conversations and meetings per rep, per list, per hour, so you can see your cold calling metrics.

What auto dialers cost: published prices

Checked on each vendor's own pricing page on 2026-10-22. Quote-only means no price is published.

For deeper comparisons see Orum vs Nooks vs Trellus, Nooks pricing and Orum pricing.

Frequently asked questions

1. 1.Supreme Court of the United States, Facebook, Inc. v. Duguid, No. 19-511 (2021)
2. 2.eCFR (FCC rules), 47 CFR 64.1200, Delivery restrictions (2026)
3. 3.FCC, Stop Unwanted Robocalls and Texts (consumer guide) (2026)
4. 4.FCC, FCC Makes AI-Generated Voices in Robocalls Illegal (2024)
5. 5.FCC, FCC Declares 'Ringless Voicemails' Are Subject to Robocalling Rules (2022)
6. 6.FTC, Complying with the Telemarketing Sales Rule (2026)
7. 7.Florida Legislature, Florida Statutes 501.059, Telephone solicitation (2026)
8. 8.PhoneBurner, Pricing (checked 2026-10-22) (2026)
9. 9.Kixie, Plans (checked 2026-10-22) (2026)
10. 10.Trellus, Pricing (checked 2026-10-22) (2026)
11. 11.Orum, Pricing (checked 2026-10-22) (2026)
12. 12.Nooks, Pricing (checked 2026-10-22) (2026)