<Tr> <Td> </Td> <Td> This section does not cite any sources . Please help improve this section by adding citations to reliable sources . Unsourced material may be challenged and removed . (November 2015) (Learn how and when to remove this template message) </Td> </Tr> <P> When telephone numbers were first used they were very short, from one to three digits, and were communicated orally to a switchboard operator when initiating a call . As telephone systems have grown and interconnected to encompass worldwide communication, telephone numbers have become longer . In addition to telephones, they have been used to access other devices, such as computer modems, pagers, and fax machines . With landlines, modems and pagers falling out of use in favor of all - digital always - connected broadband Internet and mobile phones, telephone numbers are now often used by data - only cellular devices, such as some tablet computers, digital televisions, video game controllers, and mobile hotspots, on which it is not even possible to make or accept a call . </P> <P> The number contains the information necessary to identify uniquely the intended endpoint for the telephone call . Each such endpoint must have a unique number within the public switched telephone network . Most countries use fixed length numbers (for normal lines at least) and therefore the number of endpoints determines the necessary length of the telephone number . It is also possible for each subscriber to have a set of shorter numbers for the endpoints most often used . These "shorthand" or "speed calling" numbers are automatically translated to unique telephone numbers before the call can be connected . Some special services have their own short numbers (e.g., 1 - 1 - 9, 9 - 1 - 1, 1 - 0 - 0, 1 - 0 - 1, 1 - 0 - 2, 0 - 0 - 0, 9 - 9 - 9, 1 - 1 - 1, and 1 - 1 - 2 being the Emergency Services numbers for China, Japan, India, South Korea, Taiwan and Sri Lanka; Canada and the United States; Israel (Police); Israel (Paramedic); Israel (Fire); Australia; the United Kingdom, Ireland, South Africa, Poland, Saudi Arabia, the United Arab Emirates, Morocco, Macao, Bahrain, Qatar, Bangladesh, Botswana, Ghana, Kenya, Hong Kong, Malaysia, Mauritius, Singapore, Zimbabwe, Trinidad, Tobago, New Zealand, Kuwait, the European Union and the Philippines respectively .) </P> <P> The dialing plan in some areas permits dialing numbers in the local calling area without using area code or city code prefixes . For example, a telephone number in North America consists of a three - digit area code, a three - digit central office code, and four digits for the line number . If the area has no area code overlays, seven - digit dialing may be permissible for calls within the area, but some areas have implemented mandatory ten - digit dialing . </P>

What do the digits in a phone number mean
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