Linearity and reproducibility of undersea electronics play key roles in determining the achievable performance of an undersea cable system. This paper describes the characteristics of undersea electronics and the measures taken in design and manufacture to achieve the desired performance and reliability, giving special emphasis to new features and applications. It describes in detail the performance achieved in the recently completed sg system linking the U.S. and France.

Long‐distance submarine cable transmission systems require precise, highly reliable repeaters for amplification, and adjustable equalizers for reducing accumulated transmission deviations. This article describes the problems and solutions in designing suitable repeaters and equalizers for the high capacity SF System. This system uses a repeater with transistors to provide a capacity of 800‐message circuits.