1.1. VoIP: Bridging the Gap Between
Traditional Telephony 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 (andlet's be honestchallenge 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.
1.1.1. 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 tremendous 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 importantly, that this price/performance ratio would continue
to improve as CPUs continued to increase in power.
Like so many visionaries, Dixon believed that
many others would see this opportunity, and that he merely had to
wait for someone else to create what to him was an obvious
improvement. After a few years, he noticed that not only had no one
created these cards, but it seemed unlikely that anyone was ever
going to. At that point it was clear that if he wanted a
revolution, he was going to have to start it himself. And so the
Zapata Telephony Project was born.
Since this concept was so revolutionary, and was
certain to make a lot of waves in the industry, I decided on the
Mexican revolutionary motif, and named the technology and
organization after the famous Mexican revolutionary Emiliano
Zapata. I decided to call the card the 'tormenta' which, in
Spanish, means 'storm,' but contextually is usually used to imply a
big storm, like a hurricane or such.
Perhaps we should be calling ourselves
Asteristas. Regardless, we owe Jim Dixon a debt of thanks, partly
for thinking this up and partly for seeing it through, but mostly
for giving the results of his efforts to the open source community.
As a result of Jim's contribution, Asterisk's Public Switched
Telephone Network (PSTN) engine came to be. |