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Once basic logic design theory is understood, the next step is transferring that
knowledge to a practical context that includes real components. This chapter
explains what an integrated circuit is and how off-the-shelf components can be
used to implement arbitrary logic functions. Integrated circuits, called chips
by engineers and laymen alike, are what enable digital systems as we know them.
The chapter begins with an introduction to how chips are constructed. Familiarity
with basic chip fabrication techniques and terminology enables an engineer to
comprehend the distinctions between various products so that their capabilities
can be more readily evaluated. A survey of packaging technology follows to
provide familiarity with the common physical characteristics of commercially
available chips. Selecting a package that is appropriate for a particular design
can be as critical as selecting the functional parameters of the chip itself. It is
important to understand the variety of available chip packages and why
different types of packages are used for different applications.

The chapters major topic follows next: the 7400 logic families. These off-the-shelf
logic chips have formed the basis of digital systems for decades and continue to
do so, although in fewer numbers as a result of the advent of denser components.
7400 family features are presented along with complete examples of how the
chips are applied in real designs. The purpose of this discussion is to impart a
practical and immediately applicable understanding of how digital system design
can be executed with readily available components. Although these devices
are not appropriate for every application, many basic problems can be solved
ar 7400 chips once it is understood how to employ them.

Having seen how real chips can be used to solve actual design problems, a closely
related topic is presented at the end of this chapter: the interpretation of data sheets.
Manufacturers data sheets contain critical information that must be understood to
ensure a working design. An understanding of how data sheets are organized
and the types of information that they contain is a necessary knowledge base
for every engineer.

Blakus : E-book Complete_Digital_Design

Different external serial modems use an assortment of different types of cables. Make sure the cable is actually a modem cable; other cables might fit, but that doesn’t mean they’ll work. Also try testing the cable in a cable tester. With USB cables, it is often easy to swap with a known good cable.

For information on troubleshooting network connections, see “Troubleshooting Internet Connections.”