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During the early years of telephone service, communities that required more than 10,000 telephone numbers, whether dial service was available or not, utilized exchange names to distinguish identical numerics for different customers. When dial service was introduced (typically during the period of 1910 to 1960) in such multiple exchange communities, typically, customers would dial the first two or three letters of the exchange name, followed by the numeric digits. London, England, is most notable for using the first three letters, then the last four digits. New York, USA, was the first American location to use so-called "2-5 numbers" or 2L-5D, two letters and five digits. This became the North American standard as customer-dialled long distance service (Direct Distance Dialing) came into use through the 1950s. As demand for phone service grew, the supply of assignable phone numbers began to dwindle, and several North American area codes were split to enable reuse of numbers. As the growth accelerated, the decision was made to switch to All-Number Calling (ANC), since there were several unpronounceable letter combinations that were not being used. This allowed more efficient use of the number supply; only two area code splits were necessary between 1962 and 1981. All-Number Calling was phased in slowly from 1958. Most areas had adopted it fully by the late 1960s, though it did not become universal until the 1980s. The standard format for displaying telephone numbers that used exchange names was to capitalize the first few letters if they were dialed, e.g., If they were not dialed, it was more common to only capitalize the first letter of each part of the exchange name, e.g., Such numbers could be of non-standard length, simply because they were not dialed, but quoted to an operator who plugged into the appropriate line. At least one song has been written that uses an exchange name: "PEnnsylvania Six, Five Thousand" (PE 6-5000), recorded by Glenn Miller. The use of letters in exchange names resulted in the placement of letters on the telephone dial. Some areas at first used original letter schemes (notably Calgary, Alberta) until later standardization. Europe and North America differ in placement of the letter O, and countries with non-English languages differ again.
Phase-in of All-Number Calling AT&T employed a gradual strategy to ease the transition for the customers. Originally, directory listings were printed with the exchange names spelt out in full, e.g. First stage was to print only the dialed letters: Second stage was to assign an unpronounceable combination in communities being converted from five- or fewer dialed digits to seven; no name was associated with the letters: Third stage was to assign ANC to smaller communities converting to seven-digit numbers. AT&T then proceeded to convert existing named exchanges to ANC, starting in smaller communities. No significant opposition arose until conversion began in major cities. In some cities such as San Francisco, opposition was organized. The opposition forced AT&T to slow down the conversion, and names did not totally disappear in major cities until 1975, long after AT&T had hoped to complete the conversion. Bell Canada completed most conversions of existing numbers during the first half of the 1960s. Typically in larger communities, conversions would be timed with issues of the telephone directory. For example, in London, Ontario, three conversions took place starting in February 1962 and completing in September 1963. GEneral 2, 3 and 9 were converted first; later GLadstone 1 and 5, and finally GEneral 4 and 8. | ||||||||
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