文档介绍：Source: PBX Systems for IP Telephony
CHAPTER 1
Enterprise
Communications
Systems Today
Downloaded from Digital Engineering Library @ McGraw-Hill ()
Copyright © 2004 The McGraw-panies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
munications Systems Today
2 Chapter 1
Today’s munications market is in a considerable flux
caused by major ongoing changes in the technology of core products and
work infrastructure. Notably, munications systems are
migrating from a time- to a packet-based switching and transmission
design. The last major market and product shift occurred in the mid-
1970s when the puter stored program control (SPC) and digital
munications systems were announced and shipped to
replace older generation electromechanical systems. Although every
generation believes that product upgrades and enhancements occurring
in their prime are the most significant ever, munications man-
agers who remember the limited feature and function capabilities avail-
able munications systems 30 years ago may be less impressed
with the current market upheaval than industry ers who have
learned to expect a new generation of products every 18 months from
the working world.
Today’s typical enterprise work includes
many, if not all, of the following ingredients:
1. A munications switching system (Private Branch Exchange
[PBX] system, Key Telephone System [KTS], or KTS/Hybrid system)
that provides dial tone, call setup and teardown functions, and more
call processing features than any one customer is likely to use
2. A management system to support fault and configuration operations
3. A call accounting system that analyzes and processes call detail
records to generate billing and traffic reports
4. A voice messaging system that offers a wide array of services far
beyond a basic answering system
Other widely used products that support basic voice applications in
the enterprise inc