"This new, fully updated Second Edition of Practical Data Communications is an indispensable guide for IT managers, computer scientists, system engineers, or any professional who must design or maintain data communication networks. Professionals will find it useful as a reference for precise terminology applications and practices in the field. The book stresses explanation and concepts rather than theory with current practice as the underlying theme. Roger Freeman emphasizes generalized data networks and their protocols rather than limiting the scope of the work by concentrating on proprietary systems. While most resources in the field forgo description of the underlying digital networks, discussion of PSTN as well as SONET and SDH is included here in order to allow readers to better take advantage of services available from the public network. Written to facilitate an understanding of data communications that emphasizes practical applications rather than theory, Practical Data Communications, Second Edition serves as an excellent tutorial for students or professionals with only basic understanding of the subject.