Specifications for the multiplex printing telegraph system : theory and operation (1920)
Western Union Telegraph Company · [New York?] : The Company · leaf 48
n thesending plug is inserted in the Alternating Current block, alternate impulses of positiveand negative line battery are sent to the line as the sending brushes of the distributorpass over the segments. 34. The local plug connects the local rings number 4 and number 8 to the correspondingsockets…
Telegraph
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