ZyXEL Communications ISG50 User Manual
ISG50 User’s Guide
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H A P T E R
2
Features and Applications
This chapter introduces the main features and applications of the ISG50.
2.1 Features
Voice over Internet Protocol (VoIP) Implementation
The ISG50 uses SIP (Session Initiation Protocol) to communicate with other SIP devices. SIP is an
internationally-recognized standard for implementing Voice over Internet Protocol (VoIP).
internationally-recognized standard for implementing Voice over Internet Protocol (VoIP).
The following figure shows SIP devices communicating with the ISG50.
A: IP Phones - Telephones that convert voice into IP packets and vice versa (for example ZyXEL’s
V-500).
V-500).
B: Softphones - Software-based phones installed on PCs.
C: VoIP Gateways - Devices (for example ZyXEL’s P-2302HWUDL) with built in SIP processing
which allow traditional analog phones or cordless phones to use them as a link to the IP PBX.
which allow traditional analog phones or cordless phones to use them as a link to the IP PBX.
D: ATAs - Analog Telephone Adapters (for example ZyXEL’s P-2024) aggregate a large number of
analog phones and convert their signal into IP packets.
analog phones and convert their signal into IP packets.
E: Peer IP PBXs - Other SIP based IP PBXs with which you communicate over an IP network. This
allows you to call the telephones connected to the peer IP PBX without going through a telephone
service provider.
allows you to call the telephones connected to the peer IP PBX without going through a telephone
service provider.