Simplified transmission engineering in exchange cable plant design

IMPROVEMENT in telephone sets has been responsible for significant advances in the transmission art over the years and has always been an important part of the development program. The recent introduction of an improved telephone set known as the 500-type set has probably had greater effect on the methods of designing exchange cable plant than any other set produced since the early 1920´s. Even though improvement had been large in previous sets, transmission was, in general, the controlling factor in the design of subscriber cable and for more than 25 years the general design methods had not been greatly changed. In fact, until very recently, principles in use as early as 19281 were still being applied.