Intertel - SIP Trunking
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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
Before configuring the SIP trunk it is required to go through the following checklist and make changes where necessary:
- NAT (when used) created to 3CX
- Firewall Checker passed
- Firewall SIP ALG checked and if present disabled
Further setup information can be found in our Academy: 3CX Academy Basic Course
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
Below is a short overview of the provider's capabilities and services and whether they’re supported or not:
- CLNS (Clip No Screening): Yes
- Catch All Routing: Yes
- Fax in T38: No (audio only)
- CLIR (Number Suppression): Yes
- DTMF via RFC 2833: Yes
- Outbound Codec Order: G711U, G711A, G729, G722, GSM
- 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.
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).
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.