System information
While on the surface, the idea of a speaking computer is very attractive, the reality is
that it has limited usefulness. More information about integration of text-to-speech
with Asterisk can be found in Chapter 18.
Speech Recognition
As soon as we’ve convinced computers to talk to us, we will naturally want to be able
to talk to them.
§
Anyone who has tried to learn a foreign language can begin to recognize
the complexity of teaching a computer to understand words; however, speech recog-
nition also has to take into account the fact that before a computer can even attempt
the task of understanding the words, it must first convert the audio into a digital format.
This challenge is larger than one might at first think. For example, as humans we are
naturally able to recognize speech as distinct from, say, the sound of a barking dog or
a car horn. For a computer, this is a very complicated thing. Additionally, for a tele-
phone-based speech recognition system, the audio that is received is always going to
be of very low fidelity, and thus the computer will have that much less information to
work with.
‖
Asterisk does not have speech recognition built in, but there are many third-party
speech recognition packages that integrate with Asterisk.
Conclusion
Asterisk has become extremely popular as an IVR platform. While the media only really
pays attention to Asterisk as a “free PBX,” the reality is that Asterisk is quietly taking
the IVR industry by storm. Within any respectable-sized organization, it is very likely
that the Linux system administrators are using Asterisk to solve telecom problems that
previously were either unsolvable or impossibly expensive to solve. This is a stealthy
revolution, but no less significant for its relative obscurity.
If you are in the IVR business, you need to get to know Asterisk.
§ Actually, most of us talk to our computers, but this is seldom polite.
‖ If the speech recognition has to happen from a cell phone in a noisy conference hall, it becomes near-
impossible.
396 | Chapter 17: Interactive Voice Response