Engineering features and field trial performance of a new subscriber carrier system

IN LATE WINTER of 1956, Stromberg-Carlson Company placed a new-subscriber carrier system, known as 561 carrier, on field trial operation. This system is a result of approximately 15 months of intensive effort by many people in a number of specialized fields of engineering. System layout, circuitry, filters, packaging, printed circuitry, and components all required much basic engineering to achieve the results finally obtained in this system.