3S Telefonia - SIP Trunk
About 3S S.A.
3S Group is located in Katowice, Poland, and was established in 2002. They have their own fiber-optic network with covers nearly 3500 km and a Data Center Cluster. 3S Group provides comprehensive telecommunication and data center solutions for businesses in Poland.
Reference website: https://www.3s.pl/
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): No
- Catch All Routing: Yes
- Fax T.38 support: Yes
- CLIR (Number Suppression): Yes
- DTMF via RFC 2833: Yes
- Codec Order: G711U, G711A, G722
- 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: PL
- Select Provider in your Country: 3S Telefonia
- Main trunk number: This will have been provided to you by 3S S.A. You must enter the number in the national number format (e.g. 228839120)
- Press OK
Under the “General” tab in the “Authentication” section, enter your Authentication ID and Password (these will be supplied to you by 3S S.A.).
Once you have filled in these fields as given to you by 3S S.A., scroll to the top of the page and press OK. At this point if you refresh the page you should see your 3S Telefonia Trunk appear as Registered.
Adding Additional DIDs
To associate all other DIDs/Numbers you have in your 3S Telefonia account with 3CX, go to the Management Console → SIP Trunks, double-click on your 3S Telefonia 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. 228839120) 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 3S Telefonia SIP Trunks in 3CX, all numbers should be entered in the national number format (e.g. 228839120), otherwise call routing will fail.
Outbound Caller ID
3S Telefonia Trunks do not support Clip No Screening which means you can only present numbers allocated to your trunk as Outbound Caller ID.
When configuring your Outbound Rules make sure that all national numbers are dialed either in the National (e.g. 228839120) or International (e.g. 48228839120) format. International numbers should be dialed in an International format (e.g. 0048228839120) More information about how to create Outbound Rules and how they work can be found here.
Although 3S Telefonia Sip trunks support T.38 Faxing, the option is disabled by default. To enable the option you need to contact 3S S.A. and request for the option to be enabled. Once it is enabled by 3S S.A. you need to enable the option “Enable G.711 to T.38 Fallback [BETA]” located under Settings → Fax Server in the 3CX management console. Click “OK” on the top of the page to save the setting.
Optionally you can restart the “3CX PhoneSystem 01 IVR Server” service by navigating to Dashboard → Services to have the option applied immediately.