Digital switching networks with channel switching is the most common type of telecommunication networks. As proved by practice in the world, mobile intensive spread only slightly reduces the number of fixed-line users, because most users take advantage of the two. The Latvian almost all subscribers connected to digital switching nodes (telephone exchanges). Only a few places in rural areas have remained analog type telephone exchanges. Lattelekom telephone network establishment to demonstrate the creation of digital data converted talks signal switching benefits. Given that the introduction of digital switching in Latvia was launched at the end of the last century, virtually no literature available in Latvian. In this work possible, is summarized in the key information available in publications, Lattelekom and RTU available Company training materials and author's personal experience in the development of new switching equipment at VEF Scientific Research Institute. The work consists of four parts. The first part deals with fundamental issues of digital switching. The second part contains signaling system No. 7 common signaling channel by the broadcasting part of the review. The third and fourth part contains the digital switching nodes and the network description of the two different switching systems-based. EWSD is designed for centralized management based on, S12-based on distributed control. The book is intended as a learning tool for students learning the digital switching systems. Outline has been tested as a third year Bachelor course in RTU ETF Telecommunication Institute.