The Instructograph was a paper tape-based machine used for the study of Morse code.
The contacts could operate an audio oscillator for the study of International Morse Code (used by radio), or a sounder for the study of American Morse Code (used by railroads), or a light bulb (Aldis Lamp - used by Navy ship to ship or by Heliograph).
1,725,145, was granted to Otto Bernard Kirkpatrick, of Chicago, IL, on August 20, 1929.
Most plugin outlet based instructographs would have a set of knobs that can control the speed and volume.
The latest version of the Instructograph was the model 500 which included a built in solid state oscillator.