An improved telephone set

A new common battery telephone set has been developed and is now in production which is materially better than previous types in performance and convenience to the user. This paper describes this set, and discusses, as typical of Bell System dleveopment processes, the contributions of the operating, development, and manufacturing organizations to the final design. It also describes the evaluation of the design by the controlled service trial, in terms of the results produced in actual service in the hands of the public.