VTX - SIP Trunking
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For over 30 years VTX has played a vital role in the Swiss telecom market and offers a range of business and private solutions in internet, telephony, mobile and cloud. Swiss 3CX customers can now make use of VTX’s secure and reliable SIP trunking service by easily selecting them from within the management console.
Reference website: VTX
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: G722, 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: CH
- Select Provider in your Country: VTX
- Main trunk number: This will have been provided to you by VTX. You must enter the number in the international number format (e.g. 0041123456789)
- Press OK
Under the “General” tab in the “Authentication” section, enter your Authentication ID and Password as well as the registrar address (these will be supplied to you by VTX).
Once you have filled in these fields as given to you by VTX, scroll to the top of the page and press OK. At this point if you refresh the page you should see your VTX Trunk appear as Registered.
Adding Additional DIDs
To associate all other DIDs/Numbers you have in your VTX account with 3CX, go to the Management Console → SIP Trunks, double-click on your VTX 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 International number format (e.g. 0041123456789) 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 VTX SIP Trunks in 3CX, all numbers should be entered in the International number format (e.g. 0041123456789), otherwise call routing will fail.
Outbound Caller ID
VTX Trunks support 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. 0123456789) , International (e.g. 0041123456789) or E164 format (e.g. +41123456789). More information about how to create Outbound Rules and how they work can be found here.