Getting To Know Your X6004 - ZyXEL Communications X6004 User Manual

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H A P T E R

Getting to Know Your X6004

This chapter introduces the main features and applications of the X6004.
1.1 Introduction
An IP PBX is a telephone exchange device located at a company site which allows an
organization to set up and control calls. IP stands for Internet Protocol, and PBX stands for
Private Branch Exchange. A regular company telephone switchboard is an example of a PBX.
The company's telephones are connected to the IP PBX. The IP PBX is then connected to the
outside world via connections to any combination of the following networks.
• A traditional Public Switched Telephone Network (PSTN)
• A broadband Internet connection to an Internet Telephony Service Provider (ITSP)
• An Integrated Services Digital Network/Basic Rate Interface Network (ISDN BRI)
• An Integrated Services Digital Network/Primary Rate Interface Network (ISDN PRI T1/
E1)
Each telephone connected to an IP PBX has an extension assigned to it. An extension is a
unique telephone number within an organization typically consisting of only a few digits.
People inside the company can call each other by dialing extensions. Calls to the outside world
go through the IP PBX to the PSTN, ITSP or ISDN.
Figure 1 IP PBX Example
X6004 User's Guide
ITSP
Internet
PSTN
PSTN/ISDN
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