Phelps duplex receiver/transmitter
Date: circa 1878
Inventory Number: 8041
Classification: Telephone
Dimensions:without cord: 13.6 × 7.3 × 3.7 cm (5 3/8 × 2 7/8 × 1 7/16 in.)
DescriptionA telephone duplex receiver/transmitter created by George M. Phelps and produced by the American Speaking Telephone Company, a unit of Western Union Company and the Gold and Stock Telegraph Co. The companies pooled the designs of a group including Amos Dolbear, Elisha Gray and Thomas A. Edison while they were involved in a lawsuit brought by Alexander Graham Bell. When the case was settled out of court, the American Speaking Telephone Company was dissolved.
The receiver/transmitter has an oval, hard rubber case with straight sides and a diamond pattern imprinted on top and bottom. The case contains the magnet, coils and diaphragm. Four screws secure the top and bottom of the case. The top of the case has a round button-shaped knob with a knurled edge on one end and a round, flared, mouthpiece/earpiece on the other end. Two green fabric-wrapped electrical wires emerge from the side of the case nearest the knob, and merge into one length of cord.
Inside the device, the diaphragm is cushioned with paper rings to reduce echoing.
The instrument is inscribed in a circle on the bottom, "AMERICAN SPEAKING TELLPHONE CO. NEW-YORK"; "PHELPS' DUPLEX TELEPHONE No 3671A"; and "3671."
Signedsigned: AMERICAN SPEAKING TELEPHONE CO. NEW-YORK
Inscribedinscribed: PHELPS' DUPLEX TELEPHONE No 3671A;
stamped: 3671;
inscribed: AMERICAN SPEAKING TELLPHONE CO. NEW-YORK
FunctionConversion of sound into electrical signals for transmission over a distance and conversion of electrical signals insto sound for output by telephone
ProvenanceJefferson Laboratory, Physics Department, Harvard University
Published ReferencesThis instrument is described in:
Thomas G. Hedberg, "Catalogue: Telephones, Phonographs and Related Instruments in The Collection of Historical Scientific Instruments at Harvard University." William Andrewes, Project Director (unpublished manuscript, President and Fellows of Harvard College and Thomas G. Hedberg, 1989. Fifth Draft), pp. 43-44.