Specifications for the multiplex printing telegraph system : theory and operation
A technical manual issued by the Western Union Telegraph Company around 1920 in New York, written for the engineers and operators who installed and maintained its multiplex printing telegraph equipment. The plates are line-drawn exploded assemblies, wiring schematics and sectional views of gear trains and relays, all densely labelled in hand lettering with leader lines, useful for schematic textures, diagram typography and machine-part silhouettes.
