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9-1-1 (phonetically expressed as "nine-one-one") is the emergency telephone number for the North American Numbering Plan (NANP).

It is one of eight N11 codes.

In some jurisdictions, the use of this number is reserved for true emergency circumstances only, and to use it for any other purpose (including non-emergency problems and prank calls) is a misdemeanor offense.[1][2]



In the earliest days of telephone technology, prior to the development of the rotary dial telephone, all telephone calls were operator-assisted. To place a call, the caller was required to pick up the telephone receiver and wait for the telephone operator to answer with "Number please?" They would then ask to be connected to the number he or she wished to call, and the operator would make the required connection manually, by means of a switchboard. In an emergency, the caller might simply say "Get me the police", "I want to report a fire", or "I need an ambulance/doctor". It was usually not necessary to ask for any of these services by number, even in a large city. Indeed, until the ability to dial a phone number came into widespread use in the 1950s (it had existed in limited form since the 1920s), telephone users could not place calls without operator assistance.[3] During the period when an operator was always involved in placing a phone call, the operator instantly knew the calling party's number, even if the caller couldn't stay on the line, by simply looking at the number above the line jack of the calling party. In smaller centers, telephone operators frequently went the extra mile by making sure they knew the locations of local doctors, vets, law enforcement personnel, and even private citizens who were willing or able to help in an emergency. Frequently, the operator would activate the town's fire alarm, and acted as an informational clearinghouse when an emergency such as a fire occurred. When North American cities and towns began to convert to rotary dial or, "automatic" telephone service, many people were concerned about the loss of the personalized service that had been provided by local operators. This problem was partially solved by telling people to dial "0" for the local assistance operator, if they did not know the Fire or Police Department's full number.

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