The traditional telephone system has several well-known difficulties dealing with wide-spread emergencies. However, traditional reliability numbers don't tell the whole story. Emergency planners need to be careful when hearing that the telephone system is 99.999% reliable. The quoted figures exclude performance during periods of extreme stress. While other technologies may appear to have less reliability, you need to look at performance at the limits of the curve. Other technologies may have better performance characteristics at the extreme limits. Likewise, you need to be careful about applying solutions developed for the telephone system to other types of networks. http://www.nytimes.com/2001/03/08/technology/08TOWE.html While fiber optic technology proved invaluable, other technology fell short. The cellular telephones that controllers had come to rely on were useless after the earthquake, and land lines were jammed. The walkie- talkies they had kept after converting to cell phones were few and old. "We discovered that reverting back to basic two-way radios was what we really needed," Mr. Owen said. "If there is a next time, we'll have better two-way radio communications."