How One Line of Code Crashed AT&T's Long-Distance Network

Explore the catastrophic AT&T long-distance network failure of January 15th, 1990, caused by a single line of code. Delve into the technical details of the software bug in the SS7 signaling system that led to a cascading failure, impacting 50 million calls and costing AT&T $60 million in lost revenue. Examine the subtle race condition that went undetected through code reviews and testing, and understand how it spread through 114 switches. Gain insights into the larger lessons this incident taught the telecom industry about software complexity and testing. Learn about the impact of this 9-hour outage on millions of Americans and its significance in telecommunications history.

How One Line of Code Crashed AT&T's Long-Distance Network