Wire recorders for law / office dictation and telephone recording were made almost continuously by various companies ( mainly the American Telegraphone Company ) through the 1920s and 1930s.
12.
His commission came about as he understood the operation a device used in the Navy for recording radio and telephone conversations the'telegraphone' and the manufacturer was no longer in business.
13.
Valdemar Poulsen, who had demonstrated the'Telegraphone'( the world's first magnetic recording device ) at the Paris Exhibition of 1900, succeeded in raising the efficiency and frequency to the desired level.
14.
Except for a few crude telephone-based recording devices with no means of amplification, such as the Telegraphone, it remained so until the 1920s when several radio-related developments in electronics converged to revolutionize the recording process.
15.
Fleetwood, Vormance and others of the Expedition are given a tour of the control cabin of the " Inconvenience ", which is full of scientific gear including Manganin resistance-boxes, a Tesla coil, a Poulsen's Telegraphone and more.
