The idea of adopting a standard national emergency number was thought of in 1968. The number was to be short, easy to remember and one that would be used only for providing emergency services. The Federal Communications Commission with AT&T which was the leading telephone service provider decided on using 911 as the number had not been designated for an area code, office code or any other purpose. Congress then passed legislation making 911 a number only for emergency service providers. Since then the number has been adopted all over the USA and special cells have been set up to help people who call for aid.
Many countries' public telephone networks have a single emergency telephone number, sometimes known as the universal emergency telephone number or occasionally the emergency services number, that allows a caller to contact local emergency services for assistance. The emergency telephone number may differ from country to country. It is typically a three-digit number so that it can be easily remembered and dialed quickly. Some countries have a different emergency number for each of the different emergency services; these often differ only by the last digit. Inside the European Union, 112 has been introduced as a common emergency call number during the 1990s, and is a well known emergency number in the world today alongside with 911 and 999.