Someone who wants to get to know the customs of a country frequently
receives the advice to learn the language of that country. Why? Because the differences
that distinguish the people of one country from those of another are
reflected in the language. For example, the people of the islands of the Pacific
do not have a term for war in their language. Similarly, some native tribes in
the rain forests of the Amazon use up to 100 different terms for the color green.
The reflection of a culture in its language also applies to the area of computers.
A closer look reveals that a modern telecommunications system, like the
Global System for Mobile Communication (GSM), is nothing more than a
network of computers. Depending on the application, a language has to be
developed for such a communications network. That language is the signaling
system, which allows intersystem communication by defining a fixed protocol.
The study of the signaling system provides insight into the internal workings of
a communication system.
The main purpose of this book, after briefly describing the GSM subsystems,
is to lay the focus on the communications method—the signaling
between these subsystems— and to answer questions such as which message is
sent when, by whom, and why.
Because it is not always possible to answer all questions in a brief description
or by analyzing signaling, details are covered in greater depth in the glossary.
Furthermore, most of the items in the glossary contain references to GSM
and International Telecommunication Union (ITU) Recommendations, which
in turn allow for further research.