harmonica bug

== English == === Etymology === From harmonica for the tone that activates or deactivates the device, and bug (an electronic eavesdropping device). === Noun === harmonica bug (plural harmonica bugs) An electronic eavesdropping device (bug) that attaches to a landline telephone and is activated or deactivated by a specific tone. When activated, it prevents the telephone from ringing but activates its microphone to transmit to another telephone at a remote location. Synonym: infinity transmitter