Pulse dialing is a telephone dialing method that utilizes short pulses to convey the dialed number. These pulses are created by interrupting a steady tone briefly, producing clicks similar to those heard when dialing a rotary phone.
In this dialing method, clicks represent numbers, where one click corresponds to the number one, two clicks to the number two, and so forth, up to ten clicks for the number zero. A brief pause is essential between each number to ensure accurate designation. Rotary phones naturally introduce this pause through the slow return of the rotary system, while other systems often incorporate an artificial delay.
Historically, the rapid hanging up of the phone was employed to mimic rotary clicks and bypass pay phones’ payment mechanisms in some regions. Instead of inserting money, individuals could use the hang-up button to simulate number dialing, allowing them to place calls without incurring charges on phones lacking proper safeguards against this technique.
The roots of pulse dialing trace back to the telegraph, where early operators used two keys to tap a specific number of times, indicating short or long signals. The pulse-dial system evolved to enable telegraph operators to designate the number of clicks they wanted to send, streamlining the process. When the telephone system was introduced, it adopted this established standard.
While many telephone systems still support pulse dialing, most automated systems do not. Consequently, individuals using such phones may face limitations when interacting with phone trees or other automated systems that rely on input from a touch-tone keypad. Users of rotary systems are often given the option to stay on the line to be connected to an operator, and in more modern phone tree systems, they may be permitted to use voice commands instead of pressing keys.