How It Works; Chapter 2 How It Works; Call Routing; Call Routing Terms - ZyXEL Communications IP PBX X6004 User Manual

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H A P T E R
This chapter is an overview of different logical components and how they work together to
route calls on the X6004.

2.1 Call Routing

The two main functions of any IP-PBX are routing internal calls and handling calls to and
from the outside world.
The following sections explain how these functions are performed on the X6004.

2.1.1 Call Routing Terms

The following are some terms related to ZyXEL's IP-PBX implementation.
• Extension - This is a unique number assigned to each telephone connected to the X6004.
Extensions are used to make calls between phones connected to the X6004 and to route
calls from the outside world to their correct target. Extensions fall into the following two
groups:
• SIP Extension - This is an extension assigned to a SIP (Session Initiation Protocol)
based IP phone connected to the X6004. Alternatively this could be an extension
assigned to an analog phone which connects to the X6004 via a VoIP gateway device.
• FXS (Foreign Exchange Subscriber) Extension - This is an extension assigned to an
analog phone directly connected to a port on an FXS interface card installed on the
X6004 (See
the phone sockets in your home. In your home you are a subscriber to the telephone
services of your local telephone company and when you connect an analog phone to
the X6004 you subscribe to the telephone services of the X6004.
• Authority Group - This is a set of extensions. Each extension can only belong to one
authority group. Authority groups manage extensions by allowing them to make only
certain types of calls. For example, if you create two authority groups, you can allow one
group to make local calls and long distance calls and the second authority group to make
local calls only.
• Outbound Line Group - This is a set of connections or lines going to the outside world.
• SIP Trunk - This is a connection to your ITSP (Internet Telephony Service Provider).
• Trusted Peer - This is a connection to another IP PBX or SIP server. The trusted peer
device must also specify your X6004 as a trusted peer.
X6004 User's Guide
Figure 5 on page 38.) The FXS ports on the X6004 work the same way as

How It Works

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