The problem with the PBX was
that it was massive in size and ran hot enough to keep an entire Alaskan community warm on a
subzero day.
TIP
If you want to learn more about the history of the PBX, there is a fantastic
Web site to visit: http://leegoeller.com. This is the home page of Lee Goeller,
who has been an independent telecommunications consultant working with
business customers as well as designers of telecom equipment for more than
three decades.
Although arguments could be made for satellite communication and cell phones, the next
great revolution in Internet Protocol (IP) communication was the invention of the IP-PBX.
A company called Sphere is generally recognized as the inventor of the IP-PBX; however,
it decided to go with Asynchronous Transfer Mode (ATM) communication as opposed to IP.
Figure 1.2 A Legacy PBX System
Unified Communications ??? Chapter 1 5
As such, the real revolution in IP-based communication came in late 1998??“early 1999, when it
was determined that ???network convergence??? could be provided over existing Ethernet implementations.
The fi rst IP-PBXs were incredibly crude, using IP-ready phones that plugged into
any Ethernet port, without any focus on the quality of the call or the effect of data transmission
on it. We will spend a lot more time discussing IP communication in the next section.
So far, we have spent this chapter discussing voice communication. However, we also need
to spend some time discussing software-driven communication.
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