The Engineers of the Early Multichannel Telephony Coaxial Cable Systems

Beginning in the 1920s the need for ever more telephone circuits between cities in the United States and in Europe was at first met by carrier telephone systems providing some tens of telephone circuits on pole-mounted open wires or on multipair wire cables, using the frequency-division multiplex principles outlined in Chapter 6. However, as the numbers of circuits on each pair grew, problems were encountered from crosstalk between pairs and the increasing attenuation of the signals. As the demand grew into hundreds and more circuits on each intercity route, a more efficient and cost-effective solution was sought.