Systems that automatically call customers are referred to as dialers. There are different types of dialer. The simplest dialer is the Preview Dialer. Here the customer data record is presented to the call center agent and automatically called from there. Here the agent is involved from the first pickup of the telephone to the call acceptance of the customer. A slight modification of the Preview Dialer is the Power Dialer, where the call is triggered directly at the agent. Another calling machine is the Predictive Dialer. Here, the call is set up by a central system and the call is only assigned to the call center agent once the connection with the customer has been established. This version of the dialer uses algorithms to calculate at any time how many new calls have to be set up in order to optimally utilize the call center agents. The predictive dialer usually dials significantly more calls than there are call center agents, the so-called overdialing. Predictive dialers may only be operated in compliance with legal requirements.
Consumers can register on the Robinson list so that they are not called by an automatic calling machine.