This book focuses on the application of data communications theory to the IBM PC and compatible devices. The book includes explanations of communications concepts and software and hardware compatible with PC-type devices. Its strength is in the treatment of the detailed information about communicating with mainframes, minicomputers, networks, and other PC-compatible devices. The book contains practical advice on adapter cards, modem selection, and selected communications software packages; discussions about RS232 C and the IBM Cabling System; and even a section on how to remove the computer cover. This material is very specific, and here lies one of the weaknesses of the book. The material is immediately dated by upgrades in the products discussed and by the development of new products. Although the discussion of selected products (for example, three commercial communications software packages) is helpful to someone who needs one of these three packages, the author does not mention any other communications packages, such as Procomm, which meet many of the standards he enumerates for a communications program.

Held covers most of the subjects one needs to understand to be able to communicate using the IBM PC. Chapter 1 inspires the study of PC data communications by discussing networks, electronic mail, information utilities, and bulletin boards. Chapter 2 discusses only the essential data communications concepts. In addition, the chapter contains a good discussion of Kermit and XMODEM protocols, a pin-by-pin explanation of RS232 C, and the first of many sections on SNA. The author’s explanations of SNA and SDLC are among the best I have read. Chapter 3 discusses modems and the installation of adapter cards; it covers internal modems and acoustic couplers, types of modulation, modem compatibility, modem handshaking, intelligent modems, and modem selection. The author’s comparison of standard CCITT and Bell System modems will help the communications designer avoid many difficulties. Chapter 4 discusses the functions of communications programs, giving reasons for each of these functions, and then measures four communications packages against the list of functions. The four packages are PFS, BLAST, Softerm PC, and RELAY Gold 2.0. The explanation of each package’s functions is an excellent introduction to the details of file transfer control. Chapter 5 is an introduction to packet networks and selected information utilities such as CompuServe and MCI Mail. Chapter 6 describes IRMA products in detail and discusses connecting IBM System/3x computers and 3270 networking. Chapter 7 discusses local area networks and mentions network topology and transmission media with particular emphasis on the IBM cabling system. It also discusses five local area networks: 3Com’s EtherSeries; Fox Research’s 10-Net; and IBM’s Cluster, PC Network, and Token Ring. Chapter 8 outlines some networking strategies for organizations based on their communications needs.

The typography is excellent; I only detected one typographical error. The author successfully designed the book to be modular and therefore avoided the pitfall of redundancy in succeeding chapters.

The book does not go into detail about communications theory, nor does it go into detail about data communications programs, such as programming a UART. I would not use this as a required textbook in a data communications course. I would, however, direct those who wanted to do data communications at home to read this book, especially the chapter on communications software and the one on modems. The book is also a good introduction to some communications packages, and it would help the novice avoid costly mistakes using some major information utilities. The material on larger systems--System/3x and mainframes--would be a useful introduction for a data communications trainee in industry. Because the book includes only introductory information for determining system costs, I would recommend it to managers who have to understand the general cost issues in communications but not to those who have to develop real budgets.

Although Held has written an interesting introduction to many data communications requirements, there is at least one major problem with this introduction--it leaves the reader without direction. The book does not contain a bibliography or references at the end of chapters, and the reader is left with no tools to go beyond this introduction. The book covers connections on a homogeneous network but does not discuss heterogeneous networks. Readers have no direction if they need to connect a Wang or DEC to an IBM. Even if readers are working with a homogeneous IBM network, they have no sources of additional information. The only source of information provided by this book is the vendors of the covered set of products, and they are not noted for their objectivity about systems. This book is a rich secondary resource.