Rotary dial

The rotary dial is a device mounted on or in a telephone or switchboard that is designed to send interrupted electrical pulses, known as pulse dialing, corresponding to the number dialed.

The dial is circular, about four inches (10 cm) in diameter, with 10 fingerholes cut through the outer perimeter. The dial is mounted via a shaft extending from inside the phone or mounting and sits approximately 1/4 inch (0.7 cm) above a faceplate. The faceplate is set so that through each fingerhole letters and numbers printed on the faceplate may be seen. In the US, traditional dials have letter codes displayed with the numbers under the fingerholes in the following pattern: 1, 2 ABC, 3 DEF, 4 GHI, 5 JKL, 6 MNO, 7 PRS, 8 TUV, 9 WXY and 0 Operator. However, such letter codes were not used in all countries (Australian rotary dial phones never had them). The 1 is normally set at approximately 60 degrees clockwise from the uppermost point of the dial (if one imagines a clock face over the dial, the 1 is located at approximately the 2 o'clock position), and then the numbers progress upward counterclockwise, with the 0 being at about 5 o'clock. A curved device called a fingerstop sits above the dial at the 4 o'clock position. To dial a 6, the user puts a finger in the 6 fingerhole and rotate the dial clockwise until it reaches the fingerstop. The user then pulls out the finger, and a spring in the dial returns it to the resting position. As the dial returns, electrical contacts wired through the mechanism underneath will open and close 6 times, thus sending 6 pulses to the receiving end. A centrifugal governor regulates the speed at which the dial returns under the force of the spring.

You can fake out a phone system into thinking you are dialing a phone number without ever turning a dial or pressing buttons. This method will fool the system into thinking you are using a rotary phone. To do this, first find the little button, switch, or hook that is pushed down when you hang up the phone. To "dial" the digit 1, tap it once. For the digit 2, tap it twice QUICKLY. For the digit 3, use three taps, etc. The digit 0 is ten taps.

Different pulse systems are used depending on which country you are in. Sweden uses 1 pulse to signal the number zero, and 10 pulses to signal the number nine. New Zealand uses ten pulses minus the number desired; so to dial 7, the hook must be pressed three times. For this reason, the numbers on the dial are shifted in different countries to work with their system.

Nowadays, not all phone systems and phones support this method.

See also: touch tone, dial