excerpted section
In the U.S., FCC rules require every telephone that can physically access the network to be able to dial 911, regardless of any reason that normal service may have been disconnected (including non-payment). On wired (land line) phones, this usually is accomplished by a "soft" dial tone, which sounds normal, but will only allow emergency calls. Often, an unused and unpublished phone number will be issued to the line so that it will work properly.
http://en.wikipedia.org/wiki/9-1-1
so, there are no confusion. your cell phone will work with 911. your landline phone will work (as long as its wired and connected properly with a dial tone).
