Speed dial is a function available on many telephone systems allowing the user to place a call by pressing a reduced number of keys. This function is particularly useful for phone users who dial certain numbers on a regular basis. The capability for speed dial historically dates at least as far back as 1965. Other early "instant dialers" as far back as the year 1972 also included punched card machines and magnetic tape machines.
In most cases, the user stores these numbers in the phone's memory for future use. The speed dial numbers are usually accessed by pressing a pre-determined key or keys on the phone, followed by a one or two-digit code which the user assigns to each number; however for ease of use, on many systems a call may be placed by pressing and holding one key on the numeric keypad.
Speed dialing is also available via Custom Calling features from the Telephone Company's Central Office. The numbers are programmed by the subscriber through the standard telephone dial, and speed dial calls are placed by dialing simply the digit and waiting a few seconds on a standard rotary dial phone and an older 10 key Touch Tone phone, or by dialing the number and the # key to instantly connect the call on a modern 12 key Touch Tone phone.
Most mobile phones have a contact list feature which provides similar abilities.