(Tech) Voice Frequency and carrier frequency transmission technology for cables, Philips, c. 1990 A foundational infrastructure facet that makes the modern world possible. It's a very slow steady increase from 1912, up to the late 1950's when fully transistorized amplifiers come on the scene, but exponential growth occurs with the introduction of coaxial and fiber optics. By the 1980's capabilities begin to triple or more. It probably would be hard for engineers then to image fiber optics that can now move more than a petabyte of data in a second. Condition is very good. Overall size is approximately 23.25 x 33 (inches).
