An automatic telephone dialing system that dials from a list of numbers and turns the call over to an agent when a human responds. It increases productivity in a call center, because the agents can spend their time talking rather than waiting for calls to go through as well as hanging up on busy signals and answering machines. The couple of seconds of pause you often hear when you answer a call from a telemarketer is the time it takes for the system to determine that you are a live person. See preview dialer and call center.