Dial Tone Decoder

Dial Tone Decoder in the National Security Context

A definition and brief description of Dial Tone Decoder in relation to national security is as follows:Telephone conversations are sometimes surreptitiously taped using microphones or other bugging devices. These devices run the risk of being detected. In some intelligence-gathering tapings, however, the contact telephone number may yield information that is as valuable as the actual conversation. If the content of a conversation is not essential, the contact telephone number can be obtained with a device called a dial tone recorder.