A trunk is a way for you to use your Trixbox PBX to call any regular outside number, using the same connection as your Internet connection.  In order to do this, you will need to have purchased some form of plan through a SIP (Session Initiation Protocol) Provider such as CallCentric.

Some things you will need for this section are:

• The phone number provided to you by your SIP Provider
• This Link

The link provided is because often times, a Voip provider will not always give you the correct information that you will need to enter into the trunk configuration.  The above link are several up to date trunk configurations for several Voip providers.  This takes a lot of the guess work out of setting up a trunk to work with your provider, as you can simply copy and paste the configuration that matches your provider, and then enter in your specific information.

example:

In the trixbox admin section, select “PBX” and then “PBX Settings.”  Once there, select from the left columns “Trunks.”  This will bring you to a page that allows you to add a Trunk.

The first thing you will notice is that there are far more options than simply a SIP trunk.  We will concern ourselves with those later, as they have other functions.   Select the option that says “Add SIP Trunk.”

As with most of the options in trixbox, not all of them are required to be filled in, only a select few need to be configured for the PBX to work.  Like I have said before, if you are unsure about a particular option, you can hover over the name of the option to have a little pop-up describe what that option does.

The only required fields for this setup are the follwing:

• Dial Rules
• Trunk Name
• Peer Details
• Registration String

The other options are helpful, and can be very useful, but for the purpose of this instruction, we will only stick to the required fields.  One thing to note, is that the field “Outbound Caller ID” is not required to be filled in, but can be useful if you have setup with your SIP to allow multiple Outbound CIDs.

The first thing that is important to setup with an outgoing trunk, is the Outgoing Dial Rules.  These can tend to get a bit confusing, so Asterisk has included a real nice wizard to help you along the way.  The thing to remember about Trunk Dial Rules is that they are only used for adding numbers to, or subtracting numbers from the number being sent to the trunk, and not to allow or restrict numbers that a user has dialed.  With that in mind, lets show an example of a common trunk dial rule.

Most phone calls that you place almost always require you to type a 1 before the area code and number.  And it’s really pretty annoying if you forget, and have to hang up and dial again.  So you will want to add this dial rule:

1+NXXNXXXXXX

What this rule does, is add the number 1 to any number that is dialed and sent to the trunk, if that number starts with a 3 digit area code, and is followed by a 7 digit number.  Similarly, you can also make a 1 and the area code added to a 7 digit number that is sent to the trunk with the following dial rule:

1585+NXXXXXX (where 585 is your area code).

You can use the Dial Rules Wizard that is included in trixbox to create the correct digit structure for each type of number (e.g. NXXXXXX).

Check out How to Setup a Trixbox Voip Trunk – Part 2

Also you can get your own Trixbox Virtual VOIP Server Here.