The Wikipedia articles provide information on three different types of automated telephone systems: Automated Attendants (AAs), which replace human operators and direct callers to specific extensions or departments, Automatic Call Distributors (ACDs), which route incoming calls to a group of agents based on programmable logic, and Robocalls, which use autodialers to deliver pre-recorded messages to large numbers of people. The AAs and ACDs are often used in call centers and large businesses, while robocalls are associated with political campaigns, telemarketing, and scams. All three types of systems have evolved over time, with more sophisticated features and capabilities being developed.
