Pro-technic Ediphone, 1930-1940

Dictaphones and Ediphones were sound recording devices used for efficient oral dictation in business settings. When Edison invented the phonograph, one proposed use was "dictation without the aid of stenographers." Its tinfoil playback medium lacked quality, however. Alexander Graham Bell's Graphophone (later, Dictaphone) improved the phonograph by using wax cylinders for superior playback; cylinders were also used in the competing Ediphone.