A telephone prefix is the first set of digits after the country, and area codes of a telephone number; in the
North American Numbering Plan
The North American Numbering Plan (NANP) is a telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1 and has the international calling ...
countries (country code +# ), it is the first three digits of a seven-digit phone number, 3-3-4 scheme. In other countries both the prefix and the number may have different lengths. It shows which
exchange
Exchange may refer to:
Physics
*Gas exchange is the movement of oxygen and carbon dioxide molecules from a region of higher concentration to a region of lower concentration. Places United States
* Exchange, Indiana, an unincorporated community
* ...
the remaining numbers refer to. A full telephone number is usually made up of a
country code
Country codes are short alphabetic or numeric geographical codes (geocodes) developed to represent countries and dependent areas, for use in data processing and communications. Several different systems have been developed to do this. The term ...
(required for international calls only),
area code (required for calls between telephone areas), prefix, and subscriber number.
Some places restrict certain prefixes to
fax
Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer o ...
numbers or
cell phones
A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whi ...
only; in other places such dedicated prefixes are not used.
As telephone technology advanced, the precise significance of the prefix became blurred in many places; for instance, ''485'' in London, UK, was once the GULliver exchange, but now 44-20-''7485-''xxxx is just considered one of many number blocks served by the CLKEN Kentish Town exchange.
History
In the earliest days of telephony an
operator at the exchange connected calls to a named subscriber; later, numbers were allocated to each subscriber on an exchange, but users on different exchanges could not speak to each other. As progress was made, exchanges were connected together, initially connected by the operator by
name, and later dialed by users with prefixes such as WHI (for the WHItehall exchange, hence the famous
Whitehall 1212 number for
Scotland Yard), with letters corresponding to numbers on the
dial (WHI was equivalent to # 944), later replaced by the
numerical prefixes which remain in use.
United States prefixes
In most but not all U.S. telephone areas, the prefix
555 is reserved for special services. In particular, 555-1212 is telephone information in most areas. When telephone numbers are used in television programs and movies, a significant number of viewers dial them. Numbers prefixed 555 are usually used for such fictitious use, as they are not allocated to subscribers. When the
song
A song is a musical composition intended to be performed by the human voice. This is often done at distinct and fixed pitches (melodies) using patterns of sound and silence. Songs contain various forms, such as those including the repetit ...
867-5309/Jenny
"867-5309/Jenny" is a 1981 song written by Alex Call and Jim Keller and performed by Tommy Tutone that was released on the album '' Tommy Tutone 2'', on the Columbia Records label. It peaked at No. 4 on the ''Billboard'' Hot 100 chart in May ...
was released, hundreds of calls were made to various people and organizations in the U.S. with that number. In the film ''
Bruce Almighty'' a phone number belonging to a real user was shown, leading to a lawsuit.
Prefixes ending in 11 (211, 311, 411, 511, 611, 711, 811 and 911) are disallowed prefixes because they are service codes. The prefix 958 and 959 are for
ANAC use and remain unavailable to the general public.
See also
*
Telephone numbering plan
A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, re ...
*
List of international call prefixes
The following is a list of different international call prefixes that need to be dialled when placing an international telephone call from different countries.
Countries by international prefix
Countries using optional carrier selection code ...
*
List of country calling codes
References
{{DEFAULTSORT:Telephone Prefix
Telephone numbers
eo:Telefonprefikso