Yikes. I just realized our "land line" phone is actually provided by our cable company. With a real landline phone, you can make calls out even when the power is off. With a "digital" home phone like ours (provided by the cable company), the service is dependent on the internet. When we have lost power here we have not been able to use the "land line" phone; however, we could still call out on our cell phones. The real land line is most valuable in a natural disaster type situation. Some interesting info here about the differences between these two types of phones:
http://gizmodo.com/5947158/why-cable...get-a-landline
Both types of home phones offer the address advantage for 911, I think. This is probably because the phones are associated with an exact location. If a call is made from that phone, the location of the phone is known because it is stationary. The wired land line is better in a natural disaster because it is not dependent on internet service.
Cell phones use an entirely different communication system (radio waves, I think) and it is well known that these systems become overloaded in disaster situations.