Complex issues affect the deployment of VoIP 911 services in the US

The subcommittee on Communications and the Internet will also focus on proposed legislation, which is designed to ensure that people who use Internet phone service, VoIP, can access the 911 emergency service.

While people who call 911 from a landline telephone can be traced to a specific address, this is not the case with callers who use cell phones or VoIP.

It has been established that approximately 100 million wireless 911 calls are made from cell phones every year in the United States. In some places they make up more than half of all such emergency calls. The Federal Communications Commission has just approved new rules that would force cell phone companies to use stricter standards when testing their systems to locate callers within certain distances, usually within 500 to about 1,000 feet, for 95% of the calls.

Carriers currently measure their equipment over their national service area, which means results vary from place to place. The new requirement will be phased in over the next five years.

Callers to 911 using VoIP, who can use their phones from different locations, face special challenges when calling through the Internet. Public safety dispatchers may not see a caller's name, location and telephone number automatically and service outages could disrupt the emergency service.