Push-button telephone
Modern push-button telephone
The push-button phone is a phone that buttons or keys used for dialing a telephone number to place a call to another telephone subscriber.
Western Electric 1941 already experimented with methods of mechanically actuated reed produce two tones for each of the ten digits and the late 1940s this technology was tested in a field No. 5 Sleeper switching system in Pennsylvania.But the technology proved unreliable and it was not until long after the invention of the transistor when push matured technology. On November 18, 1963, after about three years of testing the customer, the Bell System in the United States officially introduced dual-tone-multi-frequency (DTMF) technology as part of its statutory Touch Tone mark. In the coming decades, touch-tone service replaces traditional pulse dialing technology and eventually became a global standard for telecommunications signaling.
Although DTMF was the driving technology implemented in the push-button phones, some phone manufacturers are using push button keypads to generate pulse signaling dial. Before the introduction of touch-tone telephone sets, the Bell System sometimes uses the term push-button telephone to refer to key system phones that dial phones that also trigger a series of push buttons to select one of had had several telephone circuits or other functions .
History
The concept of using push buttons in telephony originated around 1887 with a device called the micro- phone button, but it was not an automatic deal as later understood. This usage predates even the invention of the rotary by Almon Strowger in 1891. The Bell System in the United States on manual switched service until 1919 when it reversed its decision and hugged selected automatic switching. 1951 introduction of the direct dialing distance requires automatic transmission of dialed numbers between remote exchanges, which leads to the use of in-band multi-frequency signals in the network, while the long rows of individual local subscribers continued to make a call by means of standard pulses.
If direct dialing distance extended by a growing number of municipalities, local numbers (often four, five or six digits) were extended to named exchanges standardized seven digits. A toll call to another area code was eleven digits, including the leading 1. In 1950, AT & T did extensive research into product engineering and efficiency and concluded that push-button dialing was preferable to rotary dialing.
After the first taste of customers in Connecticut and Illinois, about a quarter of the central office in Findlay, Ohio, was fitted in 1960 call touch-tone digits registers for the first commercial deployment of push, beginning on November 1, 1960.
On April 22, 1963, President John F. Kennedy began the countdown to the opening of the 1964 World’s Fair by dialing “1964” on a touch-tone phone in the Oval Office, the start of “a contraption that the seconds count down to the opening “. on November 18, 1963, the first electronic push-button system with touch-tone dialing was trading offered by Bell Telephone to customers in the Pittsburgh suburbs of Carnegie and Greensburg, Pennsylvania, was the DTMF system tested for several years in multiple locations, including Greensburg.
Typical push-button telephone in the 1970s and early ’80s, with 12 keys
This phone, the Western Electric in 1500, had only ten buttons. In 1968 it was replaced by the twelve-button model 2500, adding the asterisk or a star (*) keys and pound or pound sign (#). Using tones rather than pulses dial heavily on technology already developed for the long-line network, even though the 1963 touch-tone insert a different frequency set adopted for its dual-tone-multi-frequency signaling.
Although push-button touch-tone phones made their debut to the public in 1963, the telephone dial was still common for many years. In the 1970s, the majority of telephone users had rotary phones that were hired at the Bell System that time of telephone companies rather than outright ownership. Approval of the pushbutton phone was stable, but it took a long time for them to appear in some areas. At first, it was mainly companies that push button phones approved In 1979, the touch-tone phone was gaining popularity but it was not until the 1980s that the majority of customers in the hands of buttons in their homes .; By the 1990s, the vast majority.
Some fairs no longer support pulse dialing or load their few remaining users pulse dial tone dial the higher monthly tariff as rotary phones are becoming increasingly rare. Dial phones are not compatible with some modern phone features, including interactive voice response systems, although enthusiasts pulse dialing phones can adjust using a pulse-to-tone converter.
Touch-tone
The international standard for call signaling uses dual-tone-multi-frequency (DTMF) signaling, known as opting touch-tone. It replaced the older, slower system pulse dial. The push-button format is also used for all mobile phones, but with out-of-band signaling of the dialed number.
The touch-tone system makes use of audible tones for each of the digits zero to nine. Later represent this expanded with two buttons marked with an asterisk (*) and the pound or pound sign (#) to the 11th and 12th DTMF signals. These signals suitable for various additional services and customer-controlled call functions.
DTMF standard has specific frequencies for each column and row of push-buttons on the phone keypad; columns show the higher frequency in the push-button path and rows of low-frequency tones in the audible range. When a key is pressed the dial generates a combined signal of the two frequencies for the selected row and column, a dual-tone signal, which is transmitted over the phone line to the telephone exchange.
When announced the DTMF technology was not available immediately to all switching systems. The circuits of the subscribers often had to move the request to the function of the older switches that pulse dialing only supported to a newer post or have an electronic switching system in which the allocation of a new phone number that was billed at a higher monthly rate. Control Agency dial subscribers would often service initially unavailable because these villages were served by a single unattended exchange, often step by step, with the services of a foreign exchange impractical expensive. Rural party line service is usually based on mechanical switches that could not be upgraded.
While a tone-to-pulse converter can be deployed were existing mechanical office line using 1970s technology, the speed would be limited to pulse dialing rates.The new central office switches backward compatible with rotating numbers.
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