dictograph
/ˈdɪktəɡraf/ /ˈdɪktəɡrɑːf/Now historical
noun
A form of telephone by means of which speech can be picked up by a sensitive microphone and reproduced by a loudspeaker in another location in the same building.
- The dictograph was designed to be used for remote dictation to a typist but was also used for eavesdropping..
Origin
Early 20th century. From dict- + -o- + -graph, after phonograph. Perhaps compare Dictaphone.