Colt - SIP Trunking
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Colt is known for its high bandwidth network and voice services for enterprises and wholesale customers in Europe, Asia and North America. It’s an ideal solution for French businesses who wish to use 3CX in conjunction with Colt’s SIP Trunks as they are big enough to deliver and small enough to care about all their customers.
Reference website: Colt
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 v15.5 SP4
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 T.38 support: Yes
- CLIR (Number Suppression): Yes
- DTMF via RFC 2833: Yes
- Codec Order: G711A, G729
- 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: FR
- Select Provider in your Country: Colt (SIP trunking)
- Main trunk number: This will have been provided to you by Colt. You must enter the number in the E164 number format (e.g. +33184250060)
- Press OK
Under the “General” tab in the “Trunk Details” enter the registrar IP provided to you by Colt. Since this is an IP based trunk it is not required to enter an Authentication ID and Password so leave those fields empty.
Once you have filled in these fields, scroll to the top of the page and press OK.
Adding Additional DIDs
To associate all other DIDs/Numbers you have in your Colt SIP Trunking account with 3CX, go to the Management Console → SIP Trunks, double-click on your Colt SIP Trunking 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/Numbers you have to the list in E164 number format (e.g. +33184250060) and press OK.
Creating Inbound Rules
Now that you have associated all your DIDs/Numbers 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.
When configuring Colt SIP Trunking trunks in 3CX, all numbers should be entered in the E164 number format (e.g. +33184250060), otherwise call routing will fail.
Outbound Caller ID
Colt SIP Trunking supports Clip No Screening which means you can present any number as Outbound Caller ID.
When configuring your Outbound Rules make sure that all numbers are dialed either in the National (e.g. 0184250060), International (e.g. 0033184250060) or E164 (+33184250060) format. More information about how to create Outbound Rules and how they work can be found here.