The North American Numbering Plan (NANP) establishes what telephone numbers exist. It would be safe to say that most people know and understand that the short code of 911 will connect callers with police, fire or medical services in the event of an emergency. But did you know that there are seven other numbers, arguably as important?
N11的数字，或电话短码，提供快速呼叫者和简单的访问其他专项救助，可能需要不占用应急服务的资源和电话线。
Usage of these codes is established by theFederal Communications Commissionbased on use defined by theNANP Administrator, and is as follows:
- 211—Community services and information
- 311—Municipal government services
- 411—Directory assistance*
- 511-交通信息
- 611—Phone company repair*
- 711—TDD and Relay for the Deaf
- 811-地下公共设施的位置
- 911—Emergency services (police, fire, EMS)
*Note: While 411 and 611 are reserved, they have not been officially assigned by the FCC.
特殊用途保留当前的N11号
211 - 社区服务
Where available, 211 services provide free and confidential services that help people across North America. Questions about human trafficking, disaster assistance, food, health, housing utilities, as well as jobs and support for veterans or some of the services offered. Often 211 services are operated by the United Way of America. Visitwww.211.orgfor information about services available in your area.
311 - 市政府服务
Many large cities have deployed 311 services in an attempt to offload non-emergency requests from citizens. Under existing networks, these calls are sent to already over-burdened 911 centers. With 311 centers, residents can inquire about anything from trash collection to reporting graffiti. For example, theBaltimore 311center currently accepts pictures and text messages from Twitter and provides citizens with an interactive, multimedia touch point promoting good will. This level of constituent interaction makes dealing with the local government less of a hassle and an enjoyable experience.
411 – Reserved (often used for directory services)
尽管电话公司印刷出版copy of the telephone book, 411 information services are often established to provide directory assistance or local information. With payphones decreasing and cellular services at the point of saturation, usage of this local service has declined. According to the current NANP, the digits 411 are RESERVED and not assigned by the FCC for any particular service.
511 – Traffic information services
511 has been established for road and weather information as the transportation and traffic information telephone hotline. Where available, mobile and landline travelers can dial 511 for information and updates germane to their location.
611 - 保留（本地电话公司修理）
Similar to 411 services, 611 has been reserved in the NANP but not specifically assigned to a particular use. In some areas, 611 was used as a test code for linemen on the street or was used to report troubles to the central office from a subscriber.
711 - 电话设备聋人（TDD）和中转服务
Every telephone company is required to connect persons who dial 711 to a Telephone Relay Service (TRS) from a device on a working number. This rule was extended to include all VoIP telephones in July 2007 by theFederal Communications Commission.
811 – Call before you dig, mark out service
In March of 2005, the FCC established 811 as the universal number that would coordinate location services for underground public utilities. This safety measure not only helps prevents damage that interrupts telecommunications, but also the cutting of subterranean power lines, water mains and natural gas pipes.
911 – Emergencies for police, fire, medical
所有紧急服务，包括警察，消防和医疗单号访问。
Special consideration for PBX/MLTS Systems
Be sure that these numbers have been added to the dial plan of the PBX system in your office. Without them being specifically programmed, they may not be accessible.