Reverselookups

North American Numbering Plan

Many dials on fashionable telephones in use within the NANP service areas maintain the tradition of alphabetic dialing. Sometimes every pushbutton from digit two to nine additionally displays 3 letters, that is standardized in iso 9995-8 and, in europe, e.161. Traditionally, the letters q and z were omitted, though some fashionable telephones contain them. Sms-capable devices have all twenty-six letters. The alphabet is dealt out to the buttons as follows:

No letters are usually mapped to keys one and zero, though some company voicemail systems use one for q and z, and a few previous telephones allotted the z to the digit zero.

Originally, this theme was used as a mnemotechnic device for signal prefixes. Once telephone numbers within the us were standardized within the mid-20th century to seven digits, the primary 2 digits of the exchange prefix were expressed as letters instead of numbers, victimization the telephone exchange name. Before warfare ii, the most important cities used 3 letters and 4 or 5 numbers, whereas, in most cities with client dialing, phone numbers had solely six digits (2l-4n). The prefix was a reputation, and therefore the initial 2 or 3 letters, sometimes shown in capital letters, were dialed. Later, the third letter, wherever enforced, was replaced by a digit, or an additional digit was supplemental. This usually happened once warfare ii, though big apple town reborn in 1930. The adoption of seven-digit native numbers (2l-5n) was chosen because of the demand for direct distance dialing and more and more deployed beginning the late forties.

The notable miller tune pennsylvania 6-5000 refers to signal pe6-5000, variety still in commission at the edifice pennsylvania (212 736-5000). Similarly, the classic film butterfield eight is about within the side of manhattan between rough sixty-fourth and 86th streets, wherever the telephone prefixes embody 288. In some works of fiction, phone numbers can begin with "klondike five" or klamath river 5, that interprets to 555, associate degree exchange that's reserved for data numbers in north america.

The letter system was phased out, starting before 1965, though it persisted 10 years later in some places. It absolutely was enclosed in bell of pennsylvania directories till 1983. Even today, some businesses still show a 2l-5n variety in advertisements, e.g., the belvedere construction company in port, michigan not solely still uses the 2l-5n format for its variety (tyler 8-7100), it uses the format for the fee variety (1-800-ty8- 7100).

Despite the phasing out of the letter system otherwise, alphabetic phonewords stay as a poster mnemotechnic gimmick, notably for fee numbers. For instance, one will dial 1-800-flowers to order flowers, or 1-800-dentist to seek out a neighborhood medical practitioner.

In addition to business uses, alphabetic dialing has often influenced the selection of regional space codes within the us. For instance, once space 423 (east tennessee) was split in 1999, the region close city was allotted code 865, chosen to represent the word vol (volunteers), the nickname of tennessee (the volunteer state), moreover as athletic groups at the university of tennessee.[33][34] another example of this can be code 859 in american state, that was chosen to represent 'uky' as a nod to the university of the american state in lexington, ky, the code's principal town.

Several caribbean space codes were chosen as associate degree alphabetic abbreviation of the country name, that is indicated within the table of NANP regions