Telephone instruments, plastics used

The modern era of telecommunications has begun to depend on bundles of optical fibers—thin, flexible tubes of glass and plastic—to send information over long-distance telephone networks. Also used in medical instruments to examine various body cavities, such as the bladder and intestines, a fiber-optics system converts electricity to pulses of light that carry the data—much more of it, in fact, than ordinary wires, which have to use pulses of electricity-... 

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