How are telephone numbers defined in a national numbering plan?
National telephone numbers are defined by national or regional numbering plans, such as the European Telephony Numbering Space, the North American Numbering Plan (NANP), or the UK number plan . Within the national numbering plan, a complete destination telephone number is composed of an area code and a subscriber telephone number.
What is the international standard for telephone numbers?
Most national telephone administrations have enacted numbering plans that conform to the international standard E.164 . E.164 conformant telephone numbers consist of a country calling code and a national telephone number.
Is the International Telephone Union an open numbering plan?
The International Telecommunication Union (ITU) has established a comprehensive numbering plan, designated E.164, for uniform interoperability of the networks of its member state or regional administrations. It is an open numbering plan, however, imposing a maximum length of 15 digits to telephone numbers.
What is the purpose of a telephone number?
A telephone number serves as an address for switching telephone calls using a system of destination code routing. Telephone numbers are entered or dialed by a calling party on the originating telephone set, which transmits the sequence of digits in the process of signaling to a telephone exchange.
What was the purpose of the national telephone numbering plan?
For this purpose Ofcom established a telephone numbering plan, known as the National Telephone Numbering Plan, which is the system for assigning telephone numbers to subscriber stations. The numbers are of variable length.
How many national telephone numbers are there in the UK?
All mobile telephone numbers have 10 national (significant) numbers after the “0” trunk code. The overall structure of the UK’s National Numbering Plan is: A short sample of geographic numbers, set out in the officially approved (Ofcom) number groups:
What is the National significant number for 01?
Number ranges starting 01 can have National Significant Number (NSN) length as 10 or 9 digits. The 0800 range can have NSN length as 10, 9 or 7 digits. The 0845 range can have NSN length as 10 or 7 digits. The 0500 range has NSN length as 9 digits only.
How are telephone numbers assigned to a customer?
Telephone numbers are assigned within the framework of a national or regional telephone numbering plan to subscribers by telephone service operators, which may be commercial entities, state-controlled administrations, or other telecommunication industry associations.
