What Is a Dialer? Preview, Progressive, and Predictive Dialing

Anyone who has made outbound business calls by hand knows how much time is lost before a conversation even begins. Finding the next number, dialing it, listening to it ring, reaching voicemail, logging the result, and starting again. In a typical hour of manual calling, only a small part of the time is spent actually talking to people.

Dialers were created to solve that problem. They're one of the most important tools in outbound calling, and the type of dialer a business uses shapes how its calls feel, both for the people making them and the people answering them.

What Is a Dialer?

A dialer is software, usually part of a phone system or contact center platform, that places outbound calls automatically or semi-automatically from a list of contacts. Instead of dialing each number by hand, callers work from a queue of contacts that the dialer manages for them.

Most dialers do more than just dial. They typically handle the contact list itself, decide when each number should be called, record the outcome of every call, schedule retries for unanswered numbers, and display the contact's details on screen when a call connects.

The Main Types of Dialing

Dialers work in several different modes. The key differences are how much control the caller has, how many calls are placed at once, and how much waiting time is removed.

Manual and click-to-call dialing

The simplest approach. The caller sees a contact and clicks a button to dial it, or types the number themselves. Click-to-call saves a little time over dialing by hand, but the caller still controls every call and waits through every ring.

Best suited to: Small volumes of calls, high-value conversations, and situations where each call needs individual attention.

Preview dialing

The dialer shows the caller a contact's details before the call is placed, giving them time to review the information. The caller then chooses to dial, skip, or sometimes the call is placed automatically after a short countdown.

Strengths: The caller is prepared before the person answers, which suits calls where context matters, such as following up on a previous conversation or calling existing business clients.

Limitations: It's the slowest automated mode, since callers still wait through ringing and unanswered calls.

Best suited to: Complex sales, account management, collections where history matters, and business-to-business calling.

Progressive dialing

As soon as a caller finishes a call and becomes available, the dialer automatically dials the next contact. Only one call is placed per available caller, so whenever someone answers, a caller is always ready.

Strengths: It removes the time spent selecting and dialing numbers, while guaranteeing that every answered call is connected to a person.

Limitations: Callers still wait while each call rings and when calls go unanswered.

Best suited to: Moderate volumes where connecting every answered call to a person is important, and where answer rates are reasonably high.

Power dialing

Power dialing places a fixed number of calls for each available caller at the same time, for example two or three numbers at once. The first one answered is connected to the caller.

Strengths: Callers spend less time waiting for someone to pick up.

Limitations: If more than one person answers, the extra calls may have no caller available, so those people answer to silence or a short message. This makes it riskier than progressive dialing.

Best suited to: Situations with low answer rates, where the risk of multiple answers is small.

Predictive dialing

Predictive dialing is the most advanced mode. The dialer uses statistics to predict when callers will become available and how many calls are likely to be answered, then dials ahead to match. If it expects that only one in four calls will be answered, it might dial several numbers for each caller who's about to become free.

Unlike power dialing, the ratio isn't fixed. The dialer constantly adjusts based on real-time data, such as current answer rates, average call lengths, and how many callers are available.

Strengths: It keeps callers in conversation for the largest share of their time, which makes it the most efficient mode for high-volume calling.

Limitations: The prediction is never perfect. When more people answer than there are callers available, some calls are abandoned, meaning the person answers and finds no one there. This is frustrating for the person answering and is regulated in many countries.

Best suited to: Large-scale campaigns with many contacts, where efficiency matters most and answer rates are fairly predictable.

Abandoned Calls and the Rules Around Them

Abandoned calls are the central trade-off of automated dialing. The more aggressively a dialer dials ahead, the more efficient it becomes, but the more people answer to silence. Repeated silent calls can be distressing, especially for older or vulnerable people, and many people wrongly assume they're being targeted by someone malicious.

As a result, several countries set clear limits.

In the United States, the Telemarketing Sales Rule limits abandoned telemarketing calls to 3% of answered calls per campaign over a 30-day period. When a call is abandoned, a short recorded message must play within two seconds of the person's greeting, identifying the seller and providing a phone number. Unanswered calls must ring for at least 15 seconds or four rings before the dialer disconnects.

In the United Kingdom, Ofcom's guidance limits abandoned calls to 3% of live calls per campaign over any 24-hour period. An information message must play within two seconds identifying the caller, numbers that receive an abandoned call shouldn't be called again within 72 hours unless a live person is guaranteed, and unanswered calls should ring for at least 15 seconds.

Many dialers include settings to manage these limits automatically, slowing down when the abandoned rate rises and playing the required messages when a call can't be connected.

Dialers and Automated Calling Laws

Beyond abandoned calls, the use of automated dialing technology is regulated in its own right in many places.

In the United States, the Telephone Consumer Protection Act (TCPA) places restrictions on calls made with an "automatic telephone dialing system." In 2021, the US Supreme Court, in Facebook v. Duguid, ruled that this term covers equipment that uses a random or sequential number generator, which narrowed its meaning. However, other rules still apply to most automated calling, including restrictions on prerecorded and artificial voices, Do Not Call requirements, and state laws, some of which define automated dialing more broadly. Businesses using dialers should take legal advice specific to where they call.

Other Features Dialers Usually Include

Modern dialers typically come with a range of features beyond the dialing mode itself.

List management. Uploading, organizing, and prioritizing contact lists, and removing duplicates or invalid numbers.

Do Not Call filtering. Checking numbers against national and internal Do Not Call lists before they're dialed.

Time zone controls. Making sure people are only called during permitted hours in their own local time, not the caller's.

Retry rules. Deciding when and how often to try unanswered numbers again, and when to stop.

Answering machine detection. Attempting to tell whether a person or a voicemail system has answered, so callers only receive live conversations. It isn't perfect, and some people may experience a short pause or a dropped call if the system misjudges.

Voicemail drops. Leaving a prerecorded message automatically when a voicemail system answers.

Call recording and reporting. Recording calls and tracking results such as dials, contacts, conversations, and outcomes.

Integration. Connecting to customer databases so call outcomes are saved automatically.

Common Dialer Platforms

Dialers range from features built into cloud contact center platforms to dedicated dialing software. One widely used example is VICIdial, an open-source contact center system that has been popular with outbound calling operations for many years because it's free to use and highly configurable, though it needs technical knowledge to set up and maintain. Many commercial cloud platforms offer similar dialing modes as part of a wider package.

Choosing the Right Dialing Mode

The right mode depends on the type of calls being made, rather than on which is most efficient on paper.

• Use preview or manual dialing when each call needs preparation or the relationship is valuable.
• Use progressive dialing when every answered call must reach a person, but callers still need to move through lists quickly.
• Use predictive dialing when volumes are high, contacts are numerous, and the operation can carefully manage abandoned call rates.

Many operations use different modes for different campaigns, or switch modes as conditions change.

The Purpose of a Dialer

At its best, a dialer simply removes the dead time from outbound calling, so the people making calls spend more of their day in actual conversations. The choice of dialing mode is a balance between efficiency and the experience of the person answering the phone. Getting that balance right, and staying within the rules, is what separates responsible outbound calling from the kind that gives the phone a bad name.

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