The rotary dial was gradually superseded by the much quicker and easier method of push-button dialling, which uses a keypad and a multi-frequency system (introduced in 1962 as "Touch-Tone") to input numbers. Before that, however, rotary dialling was the method used. This used pulses to transmit numbers to the telephone exchange. Digits were arranged in sequence in a circular layout and an overlaid wheel was rotated (by finger) from the fixed ‘stop’ position to the desired number and back. On the return rotation, the constant telephone signal was interrupted a defined number of times – generating ‘pulses’ for the automated exchange to decode – this indicated the transmitted digit.