Fiber Optics Technician's Manual

Аннотация

Optical communication systems date back two centuries, to the “optical telegraph” invented by French engineer Claude Chappe in the 1790s. His system was a series of semaphores mounted on towers, where human operators relayed messages from one tower to the next. It beat hand-carried messages hands down, but by the mid-19th century it was replaced by the electric telegraph, leaving a scattering of “telegraph hills” as its most visible legacy.