In over 99% of locations in the United States and Canada, dialing "911" from any telephone will link the caller to an emergency dispatch center 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.
When the 9-1-1 system was originally introduced, it was advertised as the "nine-eleven" service. This was changed when some panicked individuals tried to find the "eleven" key on their telephones (this may seem bizarre and amusing, but it is important to remember that in emergencies people can easily become extremely confused and irrational). Therefore, all references to the telephone number 9-1-1 are now always made as nine-one-one — never as "nine-eleven" (See September 11, 2001 attacks). Some newspapers and other media require that references to the phone number be formatted as 9-1-1; 911 is still used occasionally but less so since the coining of 9/11 to refer to the September 11 attacks.
Dialing 911 from a mobile phone will often reach the state police or highway patrol, instead of the local 911 office. The caller will have to describe his or her exact location so that the state police can transfer the call to the correct local emergency services. It can therefore be useful to store on a mobile phone the direct phone number to the local police or other emergency services.
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 Often, an unused and unpublished phone number will be issued to the line so that it will work properly.
FCC rules also now 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 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, so users should be aware of this limitation and make other arrangements for summoning assistance in an emergency. The FCC is currently addressing this issue, and is expected to rule that 911 protocols established for wired and wireless services must also be followed for VoIP.
The number's close association with emergencies has led to "911" being used as shorthand for "emergency" in text messages sent to pagers and mobile phones. Additionally, 911 is used so pervasively in US media that other countries have sometimes had difficulty in educating children not to dial 911 for help. For example, the UK number is 9-9-9, in most of Europe and all GSM systems the number is 1-1-2, the Australian number is 0-0-0, and the Japanese numbers are 1-1-0 for the police and 1-1-9 for other emergencies. In New Zealand, although 1-1-1 is the official emergency number, dialling 911 also connects to the emergency operator. Note that many countries do not run one central emergency dispatch service but have separate numbers for police, fire and ambulance services.
Development of 9-1-1
The push for the development of a nationwide emergency telephone number came in 1957 when the National Association of Fire Chiefs recommended a single number to be used for reporting fires. In 1967 the President's Commission on Law Enforcement and Administration of Justice recommended the creation of a single number that can be used nationwide for reporting emergencies. The burden then fell on the Federal Communications Commission, which then met with AT&T in November 1967 in order to come up with a solution.
In 1968, a solution was agreed upon. AT&T had chosen the number 911, which met the requirements that it be brief, easy to remember, dialed easily, and that it worked well with the phone systems in place at the time. How the number 911 itself was chosen is not well known and is subject to much speculation. However, many feel that the number 911 was chosen to be similar to the numbers 411 (directory assistance) and 611 (repair service), which had already been in use by AT&T since 1966. Also, the North American Numbering Plan in use at the time established rules for which numbers can be used for area codes and exchanges. The middle digit of an area code must be either a 0 or 1, and the first two digits of an exchange must not be a 1. At the telephone switching station, the second dialed digit was used to determine if the number was long distance or local. If the number had a 0 or 1 as the second digit, it was long distance, and it was a local call if it was any other number. Thus, since the number 911 was detected by the switching equipment as a special number, it could be routed appropriately. Also, since 911 was a unique number, never having been used as an area code or service code, it fit into the phone system easily.
9-1-1 Emergency Telephone Number Day
9-1-1 Emergency Telephone Number Day was proclaimed, by President Reagan in 1987, to occur on the 11th day of September, the ninth month, of that year. The proclamation was made to promote the North American universal emergency telephone number 9-1-1.
See also: enhanced 911
- 911 system overview
- History of the US 911 system
- FCC rules on wireless 911 service
- National Emergency Number Association: Development of 9-1-1