rotary dial

A rotary dial is a mechanical numbering device used in older telephones to make calls. It consists of a circular platform with numbered holes from 1 to 0. To dial a number, you place your finger in the hole for the desired digit and rotate the dial clockwise until it reaches a fixed stop. When released, the dial returns to its starting position, generating electrical pulses corresponding to each number. These pulses are interpreted by the telephone network to connect your call. While largely replaced by push-button and touchscreen phones, the rotary dial remains a classic example of early telephone technology.