Page 30 - Asterisk™: The Future of Telephony

Asterisk changes all of that. With Asterisk, no one is telling you how your phone system
should work, or what technology you are limited to. If you want it, you can have it.
Asterisk lovingly embraces the concept of standards compliance, while also enjoying
the freedom to develop its own innovations. What you choose to implement is up to
you—Asterisk imposes no limits.
Naturally, this incredible flexibility comes with a price: Asterisk is not a simple system
to configure. This is not because it’s illogical, confusing, or cryptic; to the contrary, it
is very sensible and practical. People’s eyes light up when they first see an Asterisk
dialplan and begin to contemplate the possibilities. But when there are literally thou-
sands of ways to achieve a result, the process naturally requires extra effort. Perhaps it
can be compared to building a house: the components are relatively easy to understand,
but a person contemplating such a task must either a) enlist competent help or b)
develop the required skills through instruction, practice, and a good book on the
subject.

VoIP: Bridging the Gap Between Traditional and Network
Telephony

While Voice over IP (VoIP) is often thought of as little more than a method of obtaining
free long-distance calling, the real value (and—let’s be honest—challenge as well) of
VoIP is that it allows voice to become nothing more than another application in the
data network.
It sometimes seems that we’ve forgotten that the purpose of the telephone is to allow
people to communicate. It is a simple goal, really, and it should be possible for us to
make it happen in far more flexible and creative ways than are currently available to
us. Since the industry has demonstrated an unwillingness to pursue this goal, a large
community of passionate people have taken on the task.

The challenge comes from the fact that an industry that has changed very little in the
last century shows little interest in starting now.

The Zapata Telephony Project

The Zapata Telephony Project was conceived of by Jim Dixon, a telecommunications
consulting engineer who was inspired by the incredible advances in CPU speeds that
the computer industry has now come to take for granted. Dixon’s belief was that far
more economical telephony systems could be created if a card existed that had nothing
more on it than the basic electronic components required to interface with a telephone
circuit. Rather than having expensive components on the card, Digital Signal Processing
‡
(DSP) would be handled in the CPU by software. While this would impose a tremen-
dous load on the CPU, Dixon was certain that the low cost of CPUs relative to their
performance made them far more attractive than expensive DSPs, and, more impor-

2 | Chapter 1: A Telephony Revolution