Enhanced 911 Service

The official national emergency telephone number in the U.S. is 911. It connects people directly with essential emergency medical, fire, and law enforcement services. Enhanced 911, or E911, lets an operator know the exact location of a caller. This enables almost immediate dispatch of emergency aid. It works even when callers are too injured or disoriented to provide their precise location. 

Most 911 systems in the U.S. already support this capability for calls made from phones with fixed, wired connections. This includes wired phones utilizing newer technologies, such as Voice over Internet Protocol (VoIP) service (see also Voice Communication over the Internet section in this chapter). However, VoIP service requires electric power at the phone’s location to operate. As a result, VoIP telephone customers need sufficient battery backup to permit them to contact E911 during a power outage. Customers may not always be aware that their VoIP phones could fail in a power outage. 

Many wireless phones now have E911 capability. However, there are still times when location information is not reliably available from a wireless telephone. For example, this can happen when calls are made from inside large multistory buildings. This may be especially important to older adults, some of whom use a cell phone primarily for emergencies.