ZyXEL Communications X6004 User Manual

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X6004 User’s Guide
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H A P T E R
  
 How It Works
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 FXS ports on the X6004 work the same way as 
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.