Direct voice communication is the claim that spirits speak independently of the medium, who facilitates the phenomenon rather than produces it. The role of the medium is to make the connection between the physical and spirit worlds. Trumpets are often utilised to amplify the signal, and directed voice mediums are sometimes known as "trumpet mediums". This form of mediumship also permits the medium to participate in the discourse during séances, since the medium's voice is not required by the spirit to communicate. Leslie Flint was one of the best known exponents of this form of mediumship.
The fraudulent medium Ronald Edwin confessed he had duped his séance sitters and revealed the fraudulent methods he had used in his book Clock Without Hands (1955). The psychical researcher Tony Cornell investigated the mediumship of Alec Harris in 1955. During the séance "spirit" materializations emerged from a cabinet and walked around the room. Cornell wrote that a stomach rumble, nicotine smelling breath and a pulse gave it away that all the spirit figures were in fact Harris and that he had dressed up as each one behind the cabinet.
A reader radiates a 1" to 20" electrical field around itself. Cards use a simple LC circuit. When a card is presented to the reader, the reader's electrical field excites a coil in the card. The coil charges a capacitor and in turn powers an integrated circuit. The integrated circuit outputs the card number to the coil, which transmits it to the reader.
In 1880 the American stage mentalist Washington Irving Bishop published a book revealing how mediums would use secret codes as the trick for their clairvoyant readings. The Seybert Commission was a group of faculty at the University of Pennsylvania who in 1884–1887 exposed fraudulent mediums such as Pierre L. O. A. Keeler and Henry Slade. The Fox sisters confessed to fraud in 1888. Margaret Fox revealed that she and her sister had produced the "spirit" rappings by cracking their toe joints.