An auto dialer is software that dials phone numbers from a list automatically, without anyone pressing a button. When a call connects, the system either routes it to a live agent or plays a pre-recorded message. The whole point is to cut the dead time between calls so your team spends time talking, not waiting for the line to ring.
How an Auto Dialer Works
The process is straightforward. You upload a contact list, configure what happens when someone answers (transfer to agent, play audio, collect a keypress), and start the campaign. The dialer works through your list, filters out busy signals, no-answers, and voicemails based on your settings, and passes live connections to available agents.
Under the hood, most modern auto dialers run over VoIP rather than traditional phone lines. They use SIP trunks to place calls across the internet, which cuts your per-minute costs significantly compared to PSTN. Open source options like ICTBroadcast run on Asterisk or FreeSWITCH, meaning you control the entire stack on your own server.
The dialer also handles compliance tasks automatically. It respects calling windows, checks against DNC lists, and logs every call with timestamps. That matters a lot when you’re operating under TCPA rules.
Types of Auto Dialers
Not all auto dialers work the same way. There are four main modes:
- Preview dialer – shows the agent the contact record before dialing. The agent clicks to call. Slowest, but right for complex accounts where you need context first.
- Progressive dialer – dials one number per available agent automatically. No agent waits, but no call gets abandoned either. Good balance for most outbound teams.
- Power dialer – dials at a fixed ratio (say, 2 calls per agent). Slightly more aggressive; some calls get dropped if agents aren’t free in time.
- Predictive dialer – uses algorithms to dial ahead of agent availability based on expected answer rates. Highest throughput, but needs a minimum agent count to work without excessive abandonment. If you’re comparing the two, see our guide on auto dialer software for a full breakdown.
Auto Dialer vs Predictive Dialer
People use these terms interchangeably, but they’re not the same. An auto dialer is the category. A predictive dialer is a specific type within that category. Every predictive dialer is an auto dialer, but not every auto dialer is predictive.
The practical difference: predictive dialers require statistical modeling and enough agents (usually 8-10 minimum) to work correctly. With fewer agents, the prediction algorithm fails and you end up with too many abandoned calls, which puts you in TCPA trouble. For small teams, a progressive or power dialer is the smarter choice.
Who Uses Auto Dialers
The most common use cases are outbound sales, debt collection, appointment reminders, and political or non-profit outreach campaigns. Any organization that needs to reach hundreds or thousands of contacts by phone on a regular basis benefits from auto dialing.
Healthcare providers use them for patient callbacks and no-show follow-ups. Government agencies run automated notifications. Schools send attendance alerts. The voice broadcast use case is particularly common for mass notifications where you don’t need a live agent on every call.
Size doesn’t really matter. A 5-agent insurance sales team and a 500-seat call center both benefit, just at different scales and with different dialing modes.
What to Look For in Auto Dialer Software
At minimum, you need TCPA-compliant calling windows, DNC list integration, and call recording. Beyond that, the things that actually separate good software from mediocre software are CRM integration (so agents see context before they speak) and real-time dashboards (so managers can spot problems before the campaign ends).
Hosted SaaS dialers are easier to set up but cost more per seat over time. Open source, self-hosted auto dialers have a steeper initial setup but give you full control over data, customization, and cost structure. For high-volume operations running millions of calls per month, the self-hosted math usually wins.
Frequently Asked Questions
Is an auto dialer legal?
Yes, auto dialers are legal in the US and most countries when used within the rules. In the US, TCPA governs auto dialing and requires prior written consent for mobile numbers, time-of-day restrictions (8am-9pm local), and mandatory DNC compliance. Violations carry fines of $500-$1,500 per call, so the compliance features in your dialer software matter.
How many calls can an auto dialer make per hour?
It depends on your agent count and the dialing mode. A single agent on a progressive dialer might handle 40-60 live conversations per hour versus 10-15 with manual dialing. A predictive dialer with 20 agents can process thousands of dial attempts per hour. The limiting factor is usually agent capacity, not the software.
What’s the difference between an auto dialer and a robocaller?
Robocalling specifically refers to playing a pre-recorded message to everyone who answers, often without consent. An auto dialer is the tool; a robocall is one way to use it. Most legitimate business use cases connect answered calls to live agents rather than playing a recording, which is both more effective and more legally defensible.
Do I need a VoIP provider to use auto dialer software?
Yes. Modern auto dialers use SIP trunking to place calls. You’ll need a VoIP provider that supplies SIP trunk capacity. Some hosted dialer platforms bundle this; self-hosted options like ICTBroadcast let you connect any SIP provider you choose, which gives you more control over call rates and routing.
What’s a good abandonment rate for an auto dialer campaign?
FTC rules cap abandonment at 3% of answered calls for most telemarketing use cases. A well-tuned predictive dialer should stay well below that. If you’re seeing higher rates, it usually means your agent count is too low relative to your dial ratio, or your answer rate assumptions are off.
ICTBroadcast is an open source auto dialer built for high-volume outbound campaigns. It supports all four dialing modes, runs on your own server, and includes full call center features including IVR, call recording, and real-time reporting. See pricing and download options.