TRS-80 data communications systems. (book reviews) Steve Gray.

TRS-80 Data Communications Systems

Subtitled, "A guide to the operation of TRS-80 microcomputers as communication devices,' the back cover says this book "shows how any student, businessperson, or hobbyist can use the TRS-80 to communicate with information utilities and message systems.'

The eleven chapters cover the role of data communications, the fundamentals (RS-232C, ASCII, bits, bauds), the TRS-80 serial port, modems, terminals, using the TRS-80 as a terminal, the TRS-80 Model II, microcomputer-based message systems, communications for the deaf (Teletype, AMRAD, Infone), large-scale communications network, and The Future. A four-page appendix provides addresses of manufacturers and distributors of data communications products.

The 4 1/2 page glossary doesn't include all the technical words in the book, such as nibble. Although this of itself is a small thing, it is one of many indications that this book may have been produced in a hurry. The chapters that explain the technology have almost no drawings at all; apparently nobody put the manuscript in front of a beginner (actually, or figuratively) for comments. Chapters 2 and 3, on fundamentals and the TRS-80 serial port, contain two drawings altogether, despite many, many places that cry out for explanatory figures. What you get instead is over four pages of ASCII and EBCDIC codes, and over a dozen tables on programming the TRS-80 UART.

The three subsequent chapters, on modems, terminals, and using the TRS-80 as a terminal, contain many photographs and some drawing, but they are a little late for the reader who is somewhat hazy over the technology because he couldn't picture, from the previous text alone, what goes on inside the devices. The writing is rather muddy in some important places where precise exposition is needed, and a little too compact for the beginner, who usually needs a more detailed text; this reads too often like a reference manual.

The book is a disappointment, doubly so because it comes from Prentice-Hall, which usually does a top-notch job on technical books. However, if you know enough about bits and bauds, the book is quite useful in telling you what is available in data communications for the TRS-80, but in that case, you would need only about 57 of the 167 pages.

Review Grade: D