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Seamless Communications’ SIP trunking service works with 3CX to save businesses between 40 - 80% on their telco bills, whether on-premise or hosted. With over 10 years in the field, Seamless Communications offers a secure and reliable solution that is now available for use by 3CX customers by simply selecting the SIP trunk in the management console.
Reference website: Seamless-Communications
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 SP6
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: Yes
- CLIR (Number Suppression): Yes
- DTMF via RFC 2833: Yes
- Outbound Codec Order: G711A, G711U
- 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: US
- Select Provider in your Country: Seamless-Communications
- Main trunk number: This will have been provided to you by Seamless-Communications. You must enter the number in the national number format (e.g. 8135791691)
- Press OK
Under the “General” tab in the “Authentication” section, enter your Authentication ID and Password (these will be supplied to you by Seamless-Communications).
Once you have filled in these fields as given to you by Seamless-Communications, scroll to the top of the page and press OK. At this point if you refresh the page you should see your Seamless-Communications Trunk appear as Registered.
Adding Additional DIDs
To associate all other DIDs/Numbers you have in your Seamless-Communications account with 3CX, go to the Management Console → SIP Trunks, double-click on your Seamless-Communications 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/Numbers you have to the list in the national number format (e.g. 8135791691) 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 Seamless-Communications SIP Trunks in 3CX, all numbers should be entered in the national number format (e.g. 8135791691), otherwise call routing will fail.
Outbound Caller ID
Seamless-Communications Trunks support Clip No Screening which means you can present any number as an Outbound Caller ID.
When configuring your Outbound Rules, numbers can only be dialed in a 10-digit format (e.g. 8135791691), or International format (e.g. 011442033272020). More information about how to create Outbound Rules and how they work can be found here.