ISG50 User’s Guide 27
CHAPTER 1
Introducing the ISG50
This chapter gives an overview of the ISG50. It explains the front panel ports, LEDs, introduces the
management methods, and lists different ways to start or stop the ISG50.
1.1 Overview
The ISG50 combines an IP PBX with powerful routing and security features. Its flexible
configuration helps network administrators set up the network and enforce security policies
efficiently, making it an ideal solution for reliable, secure voice and data service.
1.1.1 PBX
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 a combination of the following networks:
• A traditional Public Switched Telephone Network (PSTN): ISG50-PSTN
• An Internet connection to an Internet Telephony Service Provider (ITSP): all ISG50 models
• An Integrated Services Digital Network/Basic Rate Interface Network (ISDN BRI): ISG50-ISDN
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
