Why Did Old Phone Numbers Start With Letters?
owl writes:
https://www.mentalfloss.com/article/61116/why-did-old-phone-numbers-start-letters
On I Love Lucy, whenever Lucy or Ricky Ricardo gave out their phone number, they'd say it as "Murray Hill 5-9975." Even though that may look and sound like gibberish to modern phone-users, it was perfectly normal at the time. Lucy, you got some 'splaining to do.
Phone numbers looked like this in the middle of the 20th century because of telephone exchanges-the hubs through which an area's calls would be routed. Phone subscribers were given a unique five-digit number within their service area. These would be preceded by two digits, which were identified by letters, that denoted the telephone exchange you were connected to. (Before the 1950s, some cities used three letters and four numbers, while others had two letters and three numbers. The two letter, five number format-or "2L-5N"-was eventually standardized throughout the country).
Because these telephone exchanges could only facilitate around 10,000 subscribers, many large cities had multiple hubs. The Ricardo's MUrray Hill5-9975 meant their number was 685-9975 ("Hill" and its capital H served purely as a mnemonic), with the 68, or "MU," representing the east side of Manhattan's telephone exchange. This is also why phones still have letters over the numbers (three over 2 through 8, and four over 9).
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