A key technology for autodialers is the ability to detect live human pickup and answering machine. Since there is no indication/hardware signal when a call is answered by an answering machine or voicemail system, autodialer systems have to analyze incoming audio in order to make a prediction. Today, there is no algorithm that can achieve 100% accuracy.
A regular PC, desktop or laptop, can be turned into an autodialer by using a telephony board or modem. There are software programs which can setup an autodialer like function over a physical telephone line using such hardware. It is also possible to run cheap or free autodialers without a modem or telephone line using the Internet and VoIP.
With the advancement of computer software technology at the end of the 20th century, many hardware-based telephony capabilities for auto dialing can be implemented in software. Voice modems are much less expensive and some computers have them pre-installed already. Touch tones, call transfer, call progress detection, detection of answering machine and voice mail, and other telephony card features, are available in voice modem based auto dialing systems. For simple autodialer supporting only a few phone lines per PC, telephony cards offer few advantages over simple voice modems.
However, with single systems that initiate large volumes of calls simultaneously, telephony cards offload the PC by performing most of the telephony functions (call status determination, playing music on hold, answer machine detection, etc.). Calls can likewise be cross transferred at the telephony board level.
A Smart Autodialer is an autodialer capable of personalizing messages and collecting touch tone or speech feedbacks. A speech engine is usually included for converting text to speech and recognizing speech over the phone.
To customize or personalize messages, a smart autodialer system uses message template, which contains variables that can be replaced later by actual values. For example, a time variable included in the message template can be replaced by the actual time when a phone call is made.
A semi-automatic dialer is a human controlled dialer. All actions, such as dialing, playing audio message, recording, are initiated by human, normally by the press of a key. It is a productivity tool for telemarketing agents.
An enterprise grade dialer must provide two key features. First, it must be capable of making large number of simultaneous phone calls; and second, it must provide an application programming interface (API) for system integration. Almost all enterprise grade autodialers employ computer networking technology, since voice boards have fixed number of ports and cannot be scaled up. In order to make 2000 simultaneous phone calls, for example, a group of computers have to be linked together to provide the support for that many phone lines.
Some advanced enterprise dialers are distributed dialers, i.e., independent dialers that are linked together through the Internet and controlled by a call dispatching program. With distributed computing, there is virtually no limit on scalability. All distributed dialers, by definition, can be accessed remotely.