dictograph

n.

侦听器，（电话）侦听器；

Dictograph
"The Dictograph Hears All": An Example of Surveillance Technology in the Progressive Era
鈥淭he Dictograph Hears All鈥 An Example of Surveillance Technology in the Progressive Era
Surveillance by Wiretap or Dictograph: Threat or Protection? A Police Chief's Opinion
"The Leak"and Dictographs
“DICTOGRAPH.”
Dictograph used by Burns detectives in securing evidence
Electrical security cable
Sound Evidence: An Archaeology of Audio Recording and Surveillance in Popular Film and Media.
Illegal Search and Seizure, Due Process, and the Rights of the Accused: The Voices of Power in the Rhetoric of Los Angeles Police Ch...