Zen Business Talk SIP - SIP Trunk
On this topic
About Zen Business
Zen Business Talk SIP Trunking provides a low-cost, flexible solution to 3CX customers in the UK. With over 20 years of experience offering data, voice and hosting services, Zen is able to deliver a reliable solution based on businesses individual needs.
Reference website: Zen SIP Trunking
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 SP1
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, static SI per trunk
- Fax T.38 support: No (G711 passthrough only)
- CLIR (Number Suppression): No
- DTMF via RFC 2833: Yes
- Codec Order: G711U, G711A, GSM
- NAT Support: Yes
- SRTP - No
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: UK
- Select Provider in your Country: Zen Business Talk SIP
- Main trunk number: This will have been provided to you by Zen Business. You must enter the number in the UK National number format (e.g. 02033272020)
- Press OK
Under the “General” tab in the “Authentication” section enter your Authentication ID and password (these will be supplied to you by Zen Business).
Once you have filled in the Authentication ID and Password given to you by Zen, scroll to the top of the page and press OK. At this point if you refresh the page you should see your Zen Trunk appear as Registered.
Adding Additional DIDs
To associate all other DIDs/Numbers you have in your Zen Business account with 3CX, go to the Management Console → SIP Trunks, double-click on your Zen Business 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 a National UK Number format (e.g. 02033272020) and press OK once you have finished.
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 Zen Business Talk SIP Trunks in 3CX, all numbers should be entered in the UK National number format (e.g. 02033272020), otherwise calls will fail.
Outbound Caller ID
Zen Business SIP Trunks does not support Clip No Screening which means you can only present
DID’s that are registered under the trunk. To do this you will need to format the DDIs to the UK National number format (e.g. 02033272020), but not starting with 09.
When configuring your Outbound Rules make sure that all numbers are dialed either in the National (e.g. 02033272020) or International format (e.g. 00442033272020). Numbers dialed in any other format (e.g. +442033272020) will be rejected.
More information about how to create Outbound Rules and how they work can be found here.