Slang term originally for the physical interception of telephone landlines but now generally meant to apply to all voice communications, whatever the carrier system. As a source of information this type of technical intelligence does not have a universally identical legal status, and in some countries such as Britain the material cannot be used in evidence in a criminal trial, whereas transcripts taken from recordings made under warrant in the United States, often granted under the terms of the Foreign Intelligence Surveillance Act, made be adduced in evidence.