Telegraph Sounder
date: label: date made
content: ca 1905
name: label: maker
content: Skirrow, John F.
notes: label: Description (Brief)
content: Telegraph sounders convert electrical pulses into audible sounds and are used to receive Morse code messages. The message travels as a series of electrical pulses through a wire. Short pulses make a dot, slightly longer pulses make a dash. The sequence of dots and dashes represent letters and numbers. The pulses energize the sounder’s electromagnets which move a lever-arm. The arm makes a loud “click” when it strikes a crossbar and the operator translates the pattern of sounds into the original language.
label: Description (Brief)
content: This small, portable telegraph unit was known (probably generically) as a "secret sounder" and could be attached quickly to a telegraph line for military use or for tests by maintenance crews. Containing both a key and a sounder in a closed box, the unit is associated with US Patent #760029, issued to John F. Skirrow on 17 May 1904. The patent does not specifically mention a secret sounder but explains a method of adjusting the position of the electromagnets in a sounder (or "other forms of electric signaling instruments") without affecting the angle between the armature and magnet cores. Skirrow also claimed that his innovation resulted in a simpler way of adjusting sounders.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
label: See more items in
content: Communications
label: See more items in
content: Telegraph Sounders
creditLine: label: Credit Line
content: from Western Union Corporation
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.331454
label: patent number
content: 760029
label: collector/donor number
content: 100-817
label: accession number
content: 294351
label: catalog number
content: 331454
objectType: label: Object Name
content: telegraph receiver
label: Object Name
content: telegraph sounder
physicalDescription: label: Physical Description
content: brass (overall material)
label: Physical Description
content: wood (overall material)
label: Physical Description
content: steel (overall material)
label: Measurements
content: closed: 1 3/4 in x 6 1/2 in x 4 1/2 in; 4.445 cm x 16.51 cm x 11.43 cm
label: Measurements
content: open: 2 1/4 in x 6 1/2 in x 4 1/2 in; 5.715 cm x 16.51 cm x 11.43 cm