to allow viewers to easily purchase products shown in entertainment programs , the viewers call an operator terminal . the operator terminal is networked to a central controller , which is also networked to remote terminals . remote terminal operators enter data about props used in programs , copies of which are to be offered for sale . these remote terminals transmit this data to the central controller for storage in a database . operators at the operator terminals can access the data stored at the central controller to respond calls from viewers seeking to purchase products .