Chapter 1 Getting to Know Your X6004
X6004 User’s Guide
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1.1.1 Voice over Internet Protocol (VoIP) Implementation
The X6004 uses SIP (Session Initiation Protocol) to communicate with other SIP devices. SIP
is an internationally-recognized standard for implementing Voice over Internet Protocol
(VoIP).
The following figure shows SIP devices communicating with the X6004.
A: IP Phones - Telephones that convert voice into IP packets and vice versa (for example
ZyXEL’s 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.
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.
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.
F: SIP Servers - Servers (D) located at your Internet Telephony Service Provider (ITSP)
which process outgoing calls from the X6004 and direct them to IP phones on the Internet or
traditional phones on the PSTN.
Figure 2 SIP Devices and the X6004
1.1.2 PBX Telephony Features
The X6004 allows you to set up and manage features on an internal telephone network without
relying on your telephone service provider. The following are just a few examples:
• Conference calls
• Voicemail
• Call Forwarding
The X6004 integrates with your IP network. For example you can:
PSTN
ITSP
A
B
C
D
E
F