retail eavesdropping
n.β Β«Some might picture an agent climbing a telephone pole and attaching a wire to a telephone line, but such a technique, called retail eavesdropping, is only useful for going after one phone line at a time.Β» ββNSA Rolls with Tech Changes to Keep Spying” by Lisa Vaas eWeek June 4, 2007. (source: Double-Tongued Dictionary)