Transmission Improvements in Two-Wire Switching Systems

Customer distant dialing without operator intervention is predicated on rapid dependable switching and high-quality transmission with minimum contrast from call to call. It is, therefore, mandatory that each incremental unit in each built-up connection follow the best and latest design practice and be subjected to a rigid preventive maintenance program. This paper will discuss some recent changes in two-wire switching circuits to obtain improvements in transmission following the basic guidelines of the "Notes on Distance Dialing" ("Blue Book," AT&T) and bulletins released by the various United States Independent Telephone Association (USITA) committees.