Emergency calls
The nature of IP makes it difficult
to locate network users geographically. Emergency calls, therefore,
cannot easily be routed to a nearby call center, and are impossible
on some VoIP systems. Sometimes, VoIP systems may route emergency
calls to a non-emergency phone line at the intended department.
In the US, at least one major police department has strongly objected
to this practice as potentially endangering the public.
Moreover, in the event that the
caller is unable to give an address, emergency services may be
unable to locate them in any other way. Following the lead of
mobile phone operators, several VoIP carriers are already implementing
a technical work-around.For instance, one large VoIP carrier requires
the registration of the physical address where the VoIP line will
be used. When you dial the emergency number for your country,
they will route it to the appropriate local system. They also
maintain their own emergency call center that will take non-routable
emergency calls (made, for example, from a software based service
that is not tied to any particular physical location) and then
will manually route your call once learning your physical location.