India-rubber, Gutta-percha, and Telegraph Works Company
ID Number
EM.331793
accession number
294351
collector/donor number
03-41
catalog number
331793
Description (Brief)
Telegraph keys are electrical switches used to send coded messages that travel as a series of electrical pulses through a wire. Due to special difficulties in sending pulses through long underwater cables, so-called double-current keys were used. Instead of the short dots and long dashes of land-line telegraphs, submarine telegraphs sent positive pulses and negative pulses that made the receiver move right or left. The operator pressed one lever on the key to send a positive pulse and another to send a negative pulse. The code consisted of the sequence of left and right movements recorded on a paper tape.
India-rubber, Gutta-percha, and Telegraph Works Company
ID Number
EM.330242
catalog number
330242
accession number
288763
Description (Brief)
Telegraph keys are electrical switches used to send messages in code. The message travels as a series of electrical pulses through a wire. This British key was designed for use on underwater telegraph cables. Typical telegraph keys turn the current on and off in the line. This double-current key keeps the battery on the line and reverses the direction of the current flow when the operator presses down on the lever. Setting the small lever to “receive” sends the current to a separate relay instead of through the main section of the key.
Telegraph keys are electrical switches used to send coded messages that travel as a series of electrical pulses through a wire. This British “thumb key” was designed for use on underwater telegraph cables. Typical telegraph keys turn the current on and off in the line. This double-current key keeps the battery on the line and reverses the direction of the current flow when the operator presses down on the lever. Setting the small lever to “receive” sends the current to a separate relay instead of through the main section of the key.
Telegraph keys are electrical switches used to send coded messages that travel as a series of electrical pulses through a wire. Due to special difficulties in sending pulses through long underwater cables, so-called double-current keys were used. Instead of the short dots and long dashes of land-line telegraphs, submarine telegraphs sent positive pulses and negative pulses that made the receiver move right or left. The operator pressed one lever on the key to send a positive pulse and another to send a negative pulse. The code consisted of the sequence of left and right movements recorded on a paper tape.
Telegraph keys are electrical switches used to send coded messages that travel as a series of electrical pulses through a wire. Due to special difficulties in sending pulses through long underwater cables, so-called double-current keys were used. Instead of the short dots and long dashes of land-line telegraphs, submarine telegraphs sent positive pulses and negative pulses that made the receiver move right or left. The operator pressed one lever on the key to send a positive pulse and another to send a negative pulse. The code consisted of the sequence of left and right movements recorded on a paper tape.
Telegraph keys are electrical switches used to send coded messages that travel as a series of electrical pulses through a wire. Due to special difficulties in sending pulses through long underwater cables, so-called double-current keys were used. Instead of the short dots and long dashes of land-line telegraphs, submarine telegraphs sent positive pulses and negative pulses that made the receiver move right or left. The operator pressed one lever on the key to send a positive pulse and another to send a negative pulse. The code consisted of the sequence of left and right movements recorded on a paper tape. One knob is missing from this specimen.
Telegraph keys are electrical on-off switches used to send messages in Morse code. The message travels as a series of electrical pulses through a wire. The operator moved the lever on this so-called "double speed key" from side to side to make signals. This key has a switch on the side called a circuit-closer that takes the key off-line when not in use.
Hand telegraph key with control knob arranged on a spring for side-ways motion. Contact points are on either side of key bar. A line switch is included on the base. Maker claims operators of this style key will not be affected by cramp. Reference: J. H. Bunnell & Co. Catalog, 1918, page 4.
Telegraph keys are electrical on-off switches used to send messages in Morse code. The message travels as a series of electrical pulses through a wire. The operator pushes the key’s lever down briefly to make a short signal, a dot, or holds the lever down for a moment to make a slightly longer signal, a dash. The sequence of dots and dashes represent letters and numbers. This key has a switch on the side called a circuit-closer that takes the key off-line when not in use.
Telegraph keys are electrical on-off switches used to send messages in Morse code. The message travels as a series of electrical pulses through a wire. The operator pushes the key’s lever down briefly to make a short signal, a dot, or holds the lever down for a moment to make a slightly longer signal, a dash. The sequence of dots and dashes represent letters and numbers. This key has a switch on the side called a circuit-closer that takes the key off-line when not in use. The rear adjustment screw is missing from the lever arm.
Telegraph keys are electrical switches used to send messages in code. The message travels as a series of electrical pulses through a wire. This British key was designed for testing underwater telegraph cables. The operator used the key to apply a charge then remove the charge from the cable to make certain the circuit worked. One handle is missing from this specimen.
Telegraph keys are electrical switches used to send messages in code. The message travels as a series of electrical pulses through a wire. This British key was designed for testing underwater telegraph cables. The operator used the key to apply a charge then remove the charge from a repaired cable to make certain the circuit worked.
Telegraph keys are electrical switches used to send messages in code. The message travels as a series of electrical pulses through a wire. The exact method of operating this automatic double-current key is unknown at this time. The key may have been used in laboratory experiments at King's College in London investigating submarine telegraph signaling.
Telegraph keys are electrical on-off switches used to send messages in Morse code. The message travels as a series of electrical pulses through a wire. The operator pushes the key’s lever down briefly to make a short signal, a dot, or holds the lever down for a moment to make a slightly longer signal, a dash. The sequence of dots and dashes represent letters and numbers. This key was an early refinement on Alfred Vail's original lever key.
Telegraph keys are electrical switches used to send coded messages that travel as a series of electrical pulses through a wire. Due to special difficulties in sending pulses through long underwater cables, so-called double-current keys were used. Instead of the short dots and long dashes of land-line telegraphs, submarine telegraphs sent positive pulses and negative pulses that made the receiver move right or left. The operator pressed one lever on the key to send a positive pulse and another to send a negative pulse. The code consisted of the sequence of left and right movements recorded on a paper tape.
Telegraph keys are electrical on-off switches used to send messages in Morse code. The message travels as a series of electrical pulses through a wire. The operator pushes the key’s lever down briefly to make a short signal, a dot, or holds the lever down for a moment to make a slightly longer signal, a dash. The sequence of dots and dashes represent letters and numbers. This key has a switch on the side called a circuit-closer that takes the key off-line when not in use.
Telegraph keys are electrical on-off switches used to send messages in Morse code. The message travels as a series of electrical pulses through a wire. The operator pushes the key’s lever down briefly to make a short signal, a dot, or holds the lever down for a moment to make a slightly longer signal, a dash. The sequence of dots and dashes represent letters and numbers. This key originally had a switch on the side called a circuit-closer tot take the key off-line when not in use.
Telegraph keys are electrical on-off switches used to send messages in Morse code. The message travels as a series of electrical pulses through a wire. The operator pushes the key’s lever down briefly to make a short signal, a dot, or holds the lever down for a moment to make a slightly longer signal, a dash. The sequence of dots and dashes represent letters and numbers. This key has a switch on the side called a circuit-closer that takes the key off-line when not in use.
Telegraph keys are electrical on-off switches used to send messages in Morse code. The message travels as a series of electrical pulses through a wire. The operator pushes the key’s lever down briefly to make a short signal, a dot, or holds the lever down for a moment to make a slightly longer signal, a dash. The sequence of dots and dashes represent letters and numbers. This has been identified as an early form of the "Triumph Key" made by Bunnell in the late 1880s and intended to address a problem of uneven contact wear in existing keys.
Telegraph keys are electrical on-off switches used to send messages in Morse code. The message travels as a series of electrical pulses through a wire. The operator pushes the key’s lever down briefly to make a short signal, a dot, or holds the lever down for a moment to make a slightly longer signal, a dash. The sequence of dots and dashes represent letters and numbers. The straight lever was used in the mid nineteenth century.
Telegraph keys are electrical on-off switches used to send messages in Morse code. The message travels as a series of electrical pulses through a wire. The operator pushes the key’s lever down briefly to make a short signal, a dot, or holds the lever down for a moment to make a slightly longer signal, a dash. The sequence of dots and dashes represent letters and numbers. This key is referred to as a camelback due to the curved design of the lever.