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Intertel - SIP Trunking

On this topic

About Intertel

System Preparation

3CX Version

Provider Capabilities

Configuring the Trunk with 3CX

Adding the Trunk

Adding Additional DIDs

Creating Inbound Rules

Number Format

Outbound Caller ID

Outbound Rules

About Intertel

Intertel offers a reliable SIP Trunk service for Belgian businesses. You can either signup for a VOIP Account which is a single account that allows you to register one phone number or a SIP (VoIP) trunk from which you can register multiple numbers or number blocks.

Reference website: Intertel

System Preparation

Before configuring the SIP trunk it is required to go through the following checklist and make changes where necessary:

Further setup information can be found in our Academy: 3CX Academy Basic Course

3CX Version

Some providers gained support and compatibility with 3CX on a specific product version. It is advisable to always run the latest version of 3CX to ensure ongoing compatibility.

Minimum 3CX Version: 3CX Phone System 15.5 SP2

Provider Capabilities

Below is a short overview of the provider's capabilities and services and whether they’re supported or not:

  1. CLNS (Clip No Screening): Yes
  2. Catch All Routing: Yes
  3. Fax in T38: No (audio only)
  4. CLIR (Number Suppression): Yes
  5. DTMF via RFC 2833: Yes
  6. Outbound Codec Order: G711U, G711A, G729, G722, GSM
  7. NAT Support: Yes

Configuring the Trunk with 3CX

The general instructions outlining how to add a new SIP Trunk to your 3CX installation can be found here.

Adding the Trunk

Go to “SIP Trunks” and select “Add SIP Trunk”

  • Select Country: BE
  • Select Provider in your Country: Intertel
  • Main trunk number: You can get the number from your billing portal as described above. You must enter the number in the international number format (e.g. 325114740240)
  • Press OK

Under the “General” tab in the “Authentication” section enter your Authentication ID and Password taken from the Devices section of the billing portal.

Once you have filled in these fields, scroll to the top of the page and press OK. At this point if you refresh the page you should see your Intertel Trunk appear as Registered.

Adding Additional DIDs

To associate all other DIDs/Numbers you have in your Intertel account with 3CX, go to the Management Console → SIP Trunks, double-click on your Intertel Trunk and go to the “DIDs” tab.

Here you should already see 1 entry that is the Main Trunk number you have set. Add all other DIDs/Number you have to the list in the International number format (e.g. 325114740240) and press OK once you have finished.

Creating Inbound Rules

Now that you have associated all your DIDs/Number with your SIP Trunk in 3CX, you can create Inbound Rules to set where calls will be routed when those numbers are called. Instructions on how to create Inbound Rules can be found here.

Number Format

Outbound Caller ID

Intertel trunks support Clip No Screening which means you can present any number you want when calling outbound. For this to work correctly however, in all 3CX fields where the Outbound Caller ID can be set, the number must be entered in the International number format (e.g. 325114740240).

Outbound Rules

There are no special instructions regarding Outbound Rules that are required; numbers can be dialed in any valid number format.

More information about how to create Outbound Rules and how they work can be found here.

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