North American Numbering Plan usually shown in capital letters, were dialed. Later, the third letter, where implemented, was replaced by a digit, or an extra digit was added. This generally happened after World War II, although New York City converted in 1930. The adoption of seven-digit local numbers (2L-5N) was chosen as the requirement for direct distance dialing and progressively deployed starting the late 1940s. The famous Glenn Miller tune "PEnnsylvania 6-5000" refers to telephone number PE6-5000, a number still in service at the Hotel Pennsylvania (212 736-5000) in New York. Similarly, the classic film "BUtterfield 8" is set in the East Side of
Telephone number mapping ENUM enabled agent and indicates what item of information he is looking for (email address, telephone number, web address, etc.) in the PC or terminal the number is converted to a domain name. This is sent to ENUM servers on the Internet, which send back the NAPTR records associated with the name. The access information and any priority indicated for them are stored in these. The user gets the requested address back on his PC or terminal. ENUM therefore in fact functions as a mechanism for translating a telephone number into a domain name with the requested address or number