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Most telephone networks nowadays are interconnected in the international telephone network , where the format of telephone numbers is standardized by ITU-T in the recommendation E.164, which specifies that the entire number should be 20 digits or shorter, and begin with a country prefix. In most countries, this is followed by an area code or city code and the subscriber number, which might consist of the code for a particular telephone switch. ITU-T recommendation E.123ITU-T Recommendation E. 123 or the Notation for national and international telephone numbers Recommendation E. 123 defines a standard way to write telephone numbers, e-mail addresses, and web addresses. It recommends the following formats (when dialling t describes how to represent an international telephone number in writing or print, starting with a plus sign ("+") and the country code. Telephone numbering planA Telephone numbering plan allows subscribers to make and receive telephone calls, taking different formats in different parts of the world, although the International Telecommunication Union (ITU) has attempted to promote common standards among nation st

Before a telephone callA telephone call is a connection over a telephone network between the calling party and the called party. A telephone call may consist of an ordinary voice transmission using a telephone, a data transmission when the calling party and called party are usi is connected, the telephone number must be dialA dial is a generally a flat disk, often with numbers or similar markings on it, used for displaying the setting or output of a timepiece, radio or measuring instrument In telephony and telecommunications in connection with a telephone, a dial refers, ined by the calling partyThe person who (or device that) initiates a telephone call over the public switched telephone network is the calling party . The person who (or device that) answers a telephone is the called party. The calling party is usually the party that pays the fee or callerThe term caller may refer to one of the following. Caller (telecommunications), a party that originates a call Caller (dance), a person that calls dance figures in round dances and square dances.. The called partyThe person who (or device that) answers a telephone is the called party . The person who (or device that) initiates a telephone call is the calling party. In some situations, the called party may number more than one: such an instance is known as a confer might have equipment that presents caller IDCaller ID Caller Identity Display or CID is a telephony network service that transmits the caller's telephone number to the called party's telephone equipment during the ringing signal or when the call is being set up but before the call is answered. before the call is answered.

1 History

After Philipp Reis invented the telephone in 1863, [1] Alexander Graham Bell commercialized it in 1876. It was soon used as a subscription service with the invention of the telephone switch or central office. Such an office was manned by an operator that connected the calls by personal names.

The latter part of 1879 and the early part of 1880 saw the first use of telephone numbers at Lowell, Massachusetts. During an epidemic of measles, Dr. Moses Greeley Parker feared that Lowell's four telephone operators might succumb and bring about a paralysis of telephone service. He recommended the use of numbers for calling Lowell's more than 200 subscribers so that substitute operators might be more easily trained in the event of such an emergency. Parker was convinced of the telephone's potential, began buying stock, and by 1883 he was one of the largest individual stockholders in both the American Telephone Company and the New England Telephone and Telegraph Company.

Even after the assignment of numbers, operators still connected most calls into the early 20th century; "Hello, central, get me Underwood-342"

Connecting through operators or "central" was usual until mechanical dialing of numbers became more common in the 1920s.

In North America, the digits 2-9 of phone numbers were alloted 3 letters of the alphabet apiece.

Phone numbers were not usually strictly numeric until the 1950s. From the 1920s until then, most urban areas had "exchanges" of two letters, followed by numbers. This was considered easier to remember, although in the later part of this period it required the memorization of 7 characters (the same number of characters as is usual for local calling in 2003). A word would represent the first two digits to be dialed, for example "TWinbrook" for "89" ; "BYwater" for "29"; 736-5000 was "PEnnsylvania - 6- 5 thousand".

Phone numbers were traditionally tied down to a single location, but the introduction of mobile telephones has changed this. In many countries, the practice of number portability allows customers to transfer a phone number from one local exchange carrier to another, or even from a fixed-line phone to a mobile phone.

2 External links

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1 History

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Topics: Telephone Number, Telephone Card, Telephone Switchboard...