Search results
Results From The WOW.Com Content Network
Telephone number pooling, thousands-block number pooling, or just number pooling, is a method of allocating telephony numbering space of the North American Numbering Plan in the United States. The method allocates telephone numbers in blocks of 1,000 consecutive numbers of a given central office code to telephony service providers.
The Bell System engineers expected that the first numbering plan areas to require more than the 640 possible central office codes would not occur before c. 1973. [3] The solution for expanding the numbering pool within an NPA was to remove the restriction posed by not using 0 and 1 in the middle position of central office codes.
Central office code protection was once common in communities on provincial or state boundary lines. It has been declining in use as inefficient allocation of numbering resources to the growing number of competitive local exchange carriers has caused depletion of available number prefixes, often requiring ten-digit local calls and overlay plans ...
For example, 234 235-5678 is a valid telephone number; with area code 234, central office prefix (exchange) 235, and line number 5678. The number 234 911-5678 is invalid, because the central office code must not be in the form N11. 314 159-2653 is invalid, because the office code must not begin with 1.
The North American Numbering Plan is based on a ten-digit telephone number assigned to each telephone in the telephone network. The number is composed of the three-digit numbering plan area code, a three-digit central office code, and a four-digit station or line number. Certain rules govern the numerical format of each part.
For most of the second half of the 20th century, it was possible to dial any number in the metro area with just seven digits. The entire area implemented a system of central office code protection in which no central office code was duplicated in the entire area. Each existing central office code was properly routed with each area code in the ...
Microsoft is closing down its Africa Development Centre in the continent's most populous nation Nigeria, which will lead to job losses, a spokesperson said on Wednesday. The centre, based in the ...
MTN Nigeria 0807: Globacom 0808: Airtel Nigeria 0809: 9mobile 0810: MTN Nigeria 0811: Globacom 0812: Airtel Nigeria 0813: MTN Nigeria 0814: MTN Nigeria 0815: Globacom 0816: MTN Nigeria 0817: 9mobile 0818: 9mobile 0819: Starcomms 0909: 9mobile 0908: 9mobile 0901 Airtel Nigeria 0902: Airtel Nigeria 0903: MTN Nigeria 0904: Airtel Nigeria 0905 ...