What Is a Dictograph?
The dictograph, to which much publicity is now given, by reason of its use in detective work, is an instrument for magnifying sound. It was invented by K. M. Turner of New York, in 1907.
It consists of a master station in the form of a box less than a foot long and six inches deep, and any number of sub-stations that may be required. Any voice within fifteen feet is taken by the receiving instrument and carried over the wires to any distance within about a thousand miles.
It has now been adopted by a great many business organizations as a convenient means of inter-communication.