9-1-1

9-1-1 (nine-one-one or nine-eleven) is the emergency telephone number for the North American Numbering Plan (NANP). It is one of eight N11 codes.

Functionality

In over 93% of locations in the United States and Canada, dialing "911" from any telephone will link the caller to an emergency dispatch center—called a PSAP, or Public Safety Answering Point, by the telecom industry—which can send emergency responders to the caller's location in an emergency. In some areas enhanced 911 is available, which automatically gives dispatch the caller's location, if available.

Related Topics:
Emergency - Dispatch - Emergency responders - Enhanced 911

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Dialing 9-1-1 from a mobile phone in the United States originally reached the state police or highway patrol, instead of the local public safety answering point (PSAP). The caller had to describe his/her exact location so that the agency could transfer the call to the correct local emergency services. This happens because the exact location of the cellular phone isn't normally transmitted with the voice call.

Related Topics:
Mobile phone - United States - Police - Highway patrol - Emergency services

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In 2000 the FCC issued an Order requiring wireless carriers to determine and transmit the location of callers who dial 9-1-1. They set up a phased program: Phase I transmitted the location of the receiving antenna for 9-1-1 calls, while Phase II transmitted the location of the calling telephone. The Order set up certain accuracy requirements and other technical details, and milestones for completing the implementation of wireless location services. Subsequent to the FCC's Order, many wireless carriers requested waivers of the milestones, and the FCC granted many of them. As of mid-2005, the process of Phase II implementation is generally underway, but limited by the complexity of coordination required between wireless carriers, PSAPs, local telephone companies and other affected government agencies, and the limited funding available to local agencies for the conversion of PSAP equipment to display the location data (usually on computerized maps).

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These FCC rules require new mobile phones to provide their latitude and longitude to emergency operators in the event of a 911 call. Carriers may choose whether to implement this via GPS chips in each phone, or via triangulation between cell towers. In addition, the rules require carriers to connect 911 calls from any mobile phone, regardless of whether that phone is currently active. If the phone is not active there are other ways to track the location.

Related Topics:
Latitude - Longitude - GPS - Chip - Triangulation - Tower

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In the U.S., FCC rules require every telephone that can physically access the network to be able to dial 911, regardless of any reason that normal service may have been disconnected (including non-payment). On wired (land line) phones, this usually is accomplished by a "soft" dial tone, which sounds normal, but will only allow emergency calls. Often, an unused and unpublished phone number will be issued to the line so that it will work properly.

Related Topics:
FCC - Payment - Land line - Dial tone - Phone number

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If 911 is dialed from a commercial VoIP service, depending on how the provider handles such calls, the call may not go anywhere at all, or it may go to a non-emergency number at the public safety answering point associated with the billing or service address of the caller. Because a VoIP adapter can be plugged into any broadband internet connection, the caller could actually be hundreds or even thousands of miles away from home, yet if the call goes to an answering point at all, it would be the one associated with the caller's address and not the actual location. It may never be possible to accurately pinpoint the exact location of a VoIP user (even if a GPS receiver is installed in the VoIP adapter, it will likely be indoors, and may not be able to get a signal), so users should be aware of this limitation and make other arrangements for summoning assistance in an emergency.

Related Topics:
VoIP - Broadband

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In March 2005, commercial Internet telephony provider Vonage was sued by the Texas attorney general, who alleged that their website and other sales and service documentation did not make clear enough that Vonage's provision of 911 service was not done in the traditional manner.

Related Topics:
March 2005 - Internet telephony - Vonage - Attorney general

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In May 2005 the FCC issued an Order requiring VoIP providers to offer 9-1-1 service to all their subscribers within 120 days of the Order being published. The Order has set off anxiety among many VoIP providers, who feel it will be too expensive and require them to adopt solutions that won't support future VoIP products.

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