Switching to VoIP

This is the Title of the Book, eMatter Edition

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

330

Chapter 14

CHAPTER 14

Traditional Apps on the Converged

Network

When first designed, landline phone service was intended to carry sound signals, and

its uses as a carrier of data were years away from realization. It’s ironic that the tech-

nology that predated the telephone was itself a data transport technology: the tele-

graph. This device carried encoded messages from terminal to terminal across the

19

th

-century equivalent of a peer-to-peer network.

A lifetime later, in the 1960s, sound-encoding devices emerged, and, very soon, com-

puters were able to send data, represented as sound, across the telephone network.

Those devices were modems, and later fax machines—the descendants of the tele-

graph. Modems, fax machines, voice mail systems, emergency 911 service, and a

slew of other messaging tools evolved around the international telephone network.

Today voice and data networks converge and VoIP begins to replace Bell’s brain-

child. IP telephony has the same fundamental goal as legacy telephony: facilitate

human interaction at a distance. But, since IP telephony goes about this goal differ-

ently, not all of the specialized devices that evolved around the old system work with

the new one. Fax machines, modems, and voice mail systems aren’t necessarily com-

patible with VoIP, because ...