This book is organized for the presentation of a course. It is divided into eight chapters, each of which starts with a stated set of objectives, and most of which end with a set of problems designed to check the reader’s understanding of that chapter’s material.

Chapter 1 provides the historical background of computing. It discusses how communications become so important to computing early in its evolution and presents a “big picture” of the organization of digital communications.

Chapter 2 describes the devices and the low-level protocols used by them in digital communications. It discusses the logical and electrical characteristics of the various transmission techniques used in communications. The author also examines the techniques used to limit errors during transmission.

Chapter 3 presents link-level protocols and describes how data transfers are managed at the logical link level. This includes error control, flow control, and connection control.

Chapter 4 discusses the electrical interfaces which perform the actual data transfer between the interconnected devices. It covers the characteristics of several of the types of physical transmission media used to transfer signals representing digital data. It describes several of the more common physical interconnection standards, such as RS-232C, RS-422, and RS-449. It also discusses the use of modems to convert the digital signals to analogue (or another digital form) and back for transmission over longer distances or through a telephone network.

Chapter 5 describes terminal-based networks, including character-mode and block-mode interactive terminals, data-entry terminals and remote-job-entry terminals. The simpler types of terminals tend to use asynchronous, character-oriented protocols, with or without flow control and/or echo-checking error control. The more complex types of terminals tend to use synchronous, block-oriented protocols, with flow control and error control.

Chapter 6 discusses the ISO Reference Model for Open Systems Interconnection [1]. It covers the reasons for its existence, the operations assumed to occur at each level of the model, and how several of the more commonly used protocols fit into the structure of the model.

Chapter 7 describes the protocols and organization of the primary types of public data networks. These include circuit-switched and packet-switched structures, both of which are implemented in the lower three levels of the ISO Reference Model discussed in the previous chapter. It covers the interface equipment normally used to attach customer devices into the public data network.

Chapter 8 discusses Local Area Networks and the different topologies and transmission media commonly used in their implementation. This include the alternatives of baseband versus broadband signalling and CSMA versus token-passing. It also covers the concept of gateways, which allow the interconnection of separate networks.

The book seems quite adequate in introducing the reader to the concept of data communications, especially as applied to the networking of computers and/or terminals. It does not provide the reader with any idea of the relative practical importance of concepts and makes no attempt to be complete in its presentation. Specifically, IBM BISYNC protocol is briefly and inaccurately presented and IBM SDLC protocol is not specifically described (although the generic HDLC protocol is described in detail), despite their major importance in practical data communications. Some of the chapters seem out of order, especially in the description of the low-level electrical interface after the link-level protocols. Notwithstanding these problems, the book is still highly recommended as an introduction to the theory of data communications.