Transmission maintenance of telephone systems

This paper is divided into two parts. The first, part deals with the broad aspects of modern telephone transmission maintenance, the economic justification for good maintenance, and the general lines upon which it should be carried out. The second part gives the theoretical considerations leading up to the development of a series of testing instruments, by means of which transmission losses in any part of the telephone system can easily be measured. This part also contains brief descriptions of the instruments and their use.