Similar-sounding letters would cause confusion, so distinct names or phrases were preferred.
This is also why phones still have letters over the numbers (three over 2 through 8, and four over 9).įull words were used to help customers remember the telephone exchange name, and because they were easy to understand, especially for switchboard operators. 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. Because these telephone exchanges could only facilitate around 10,000 subscribers, many large cities had multiple hubs.
