Switching to VoIP

This is the Title of the Book, eMatter Edition

Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.

Basic Call Handling

|

95

Application Terminology

Many PBX vendors refer to their telephony functions using words like actions or

routes or forwarding plans. Others, the author included, prefer another word: appli-

cations. This word is appropriate for a modern, soft-driven telephony world. The

words function and action invoke an algorithmic meaning, while application is much

more broad and programmatic. Traditional TDM systems and VoIP systems have a

similar distinction: TDM is monolithic, rigid; VoIP is programmable, flexible.

But whatever the semantics, things the network can do with a phone call are referred

to in this book as applications. They’ve been organized here in five groups: basic call

handling, administrative, messaging, advanced call handling, and CTI. What’s cov-

ered in this chapter is by no means an exhaustive study of telephony apps. Indeed,

while I was busy writing this book, new apps were being developed.

Applications themselves are invented out of necessity and driven by market forces

more than by the creativity of technologists. When the market demand for certain

functionality reaches a boiling point, a vendor or a group of vendors produce a solu-

tion to the demand. Sometimes the solution is submitted to the ITU, ANSI, or IETF

for recommendation as a standard.

Not ...