The nature of IP makes it difficult to locate network users geographically. Emergency calls, therefore, cannot easily be routed to a nearby call center. Sometimes, VoIP systems may route emergency calls to a non-emergency phone line at the intended department; in the United States, at least one major police department has strongly objected to this practice as potentially endangering the public. VoIP Enhanced 911 (E911) is a method by which VoIP providers in the United States support emergency services. The VoIP E911 emergency-calling system associates a physical address with the calling party’s telephone number as required by the Wireless Communications and Public Safety Act of 1999. All VoIP providers that provide access to the public switched telephone network are required to implement E911, a service for which the subscriber may be charged. However participation in E911 is not required and customers who chose a home phone alternative may opt-out of E911 service altogether.
One shortcoming of VoIP E911 is that the emergency system is based on a static table lookup. Unlike in cellular phones, where the location of an E911 call can be traced using Assisted GPS or other methods, the VoIP E911 information is only accurate so long as subscribers are diligent in keeping their emergency address information up-to-date. In the United States, the Wireless Communications and Public Safety Act of 1999 leave the burden of responsibility upon the subscribers and not the service providers to keep their emergency information up to date.
In June of 2007 the Canadian Radio-television and Telecommunications Commission (CRTC) mandated all VoIP service providers to make 911 services available to their fixed/non-native and nomadic VoIP subscribers. VoIP service providers connect the IP realm and the Public Switched Telephone Network (PSTN), allowing subscribers to benefit from increased efficiency by routing calls over the Internet.
The CRTC decision obliges VoIP service providers to deliver all 911 calls to the appropriate Public Safety Answering Point (PSAP) using the zero-dialed emergency call routing service (0-ECRS), rather than PSAP low-priority lines. Adherence to this decision is mandatory for all VoIP service providers offering services in Canada, and is designed to protect the safety of VoIP users who expect that when they dial 911, they will quickly be connected to qualified emergency responders.
If you are to use VoIP to save several hundred dollars then it is one of the tasks you have to keep in the list of things to do when moving (Update your address on your VoIP provider Account) Most do support E911 and you should steer away from those that do not offer such an interface. Having said that reputable VoIP providers in Canada do offer a full disclosure of the E911 service they offer as you are signing in for their service.