Crossbar toll switching system

Gilbert Sorber (nonmember; Automatic Electric Company, Chicago, Ill.): It is most interesting to note the great amount of progress in and recognition of the application of automatic-switching principles to the switching of toll lines, and to the adaption of key-control operators equipment placed in service in Philadelphia. The paper quite comprehensively presents a picture of the basic switching principles and the technical problems involved. It appears, however, that the equipment is limited to major toll centers, wherein panel or crossbar equipment is employed for local services. The paper deals extensively with crossbar switching mechanism. This, we assume, is because it discusses the application of a particular manufacturer´s type of equipment, and is not a controlling factor in arriving at the desired switching accomplishments.