Telephone System Call Routing
Info
- Level: Beginner
- Presenter: Eli the Computer Guy
- Date Created: August 8, 2010
- Length of Class: 60 Minutes
Tracks
Prerequisites
Purpose of Class
- This class discusses how calls get routed within a telephone system PBX.
Topics Covered
- Extensions
- Call Paths
- Out Calling
- Incoming Trunk Groups
- Auto Attendants
- Hunt Groups
- Call Groups
- Out Going Call Routing
Class Notes
- Introduction
- All telephone systems use the same basic concepts to route calls
- Extensions
- PBX’s relate to everything as an extension. A station is an extension. An Auto Attendant is an extension, etc.
- You should create a range of extensions for use for stations and subscribers, and a different range of extensions to be used for administrative purposes (Auto Attendants, Hunt Groups, etc)
- You can determine how many numbers make up an extension (2,3,4)
- Call Paths
- Call paths determine how an incoming call is routed.
- A standard call path states that a station is rung 3 times, and then the call is routed to voicemail.
- You can have call paths with 20+ steps.
- Out Calling
- Out calling allows the PBX to route calls from the outside to outside lines. A call from the outside can be routed to a cell phone.
- Out calling requires 2 trunk lines (1 for the incoming call, and one for the outgoing call)
- Out calling can be a HUGE security problem if not administered properly.
- Incoming Trunks
- Incoming trunk lines are programmed into Trunk Groups.
- Individual Trunk Groups are pointed at a specific extension for incoming calls (Usually an Auto Attendant)
- Multiple businesses in the same building can use the same PBX by putting their phone lines into Trunk Groups and then pointing the Trunk Group to their Auto Attendant.
- Auto Attendants
- “If you would like Sales press 1”
- The message for the Auto Attendant resides on the Voicemail System.
- You create an Extension, make it an Auto Attendant, point the message to a Voicemail box, determine what will happen when users press number keys, determine what happens if the user does nothing.
- Hunt Groups
- Are Extensions that when called ring a series of other extensions in order.
- If the first extension in the hunt Group is busy, the next extension in the Hunt Group is rung.
- Weighted or Smart Hunt Groups can route calls to extensions based on programmed parameters.
- Call Groups
- Call Groups are Extensions where numerous Extensions are rung at the same time when the Extension is dialed.
- Outgoing Call Routing
- You can create Outgoing Trunk Groups based on whether the trunk lines have local, long distance, or international calling privileges.
- You can create codes to allow managers to be able to access any Outgoing Trunk Group.
- Outgoing Call Routing is based on the number of digits dialed, and whether those digits match a pattern that allows the call to be routed to a specific Outgoing Trunk Group.



Hi Everymanit,
Thanks for your telephone system videos, it’s a great job. I have a question on PBX
1. How can i slave a secondary pbx to a main (primary) pbx such that;
a. the ext. on the secondary will interact with the ext on the primary
b. the secondary will use an extension or two from the primary as its own trunk lines
c. the secondary extension will be able to use the primary trunk as its dial out route to the public
I hope this is possible? if not , kindly tell me the best that obtain base on my needs above.
Thanks for your anticipated reply.
This all depends on the PBX you are using. These are options that may or may not be built in, or turned on. You will have to look at your documentation and see what you are able to do. Generally high quality PBX’s will be able to do this, but how you configure them will be different.
Its like the difference between Windows, Linux and Mac. Yes you can share files on a network, but the way you will do it on Windows will be very different from how you do it on a Linux Server.