Deutsche Telefon Standard - SIP Trunk
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About Deutsche Telefon
Founded in 2007, Deutsche Telefon is one of the leading SIP trunk providers in Germany. In combination with 3CX’s software PBX, customers using Deutsche Telefon’s SIP trunks can enjoy a reliable, powerful and cost effective solution.
Reference website: Deutsche Telefon
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 SP2
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
- NAT Support: Yes
- 302 Diversion 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: DE
- Select Provider in your Country: Deutsche Telefon Standard AG
- Main trunk number: This will have been provided to you by Deutsche Telefon. You must enter the number in the National number format (e.g. 05114740240)
- Press OK
Under the “General” tab in the “Authentication” section enter your Authentication ID and Password (these will be supplied to you by Deutsche Telefon).
Once you have filled in these fields as given to you by Deutsche Telefon, scroll to the top of the page and press OK. If you refresh the page you should see your Deutsche Telefon Trunk appear as Registered.
Adding Additional DIDs
To associate all other DIDs/Numbers you have in your Deutsche Telefon account with 3CX, go to the Management Console → SIP Trunks, double-click on your Deutsche Telefon 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 number format (e.g. 05114740240) 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.
3CX - DTMF Setting
When creating a Deutsche Telefon Standard SIP trunk you will need to navigate to Settings → Parameters and search for value “MSADDRFC2833FORINBANDDTMF”. Double click to edit the parameter and set its value to “0” (default value is 1). This is required as Deutsche Telefon sends DTMF both In-band and RFC2833 and we only require RFC2833. This should not affect the operation of any other 3CX support provider that you may have configured on your 3CX installation.
Deutsche Telefon - Password Reset
Deutsche Telefon, as an anti-fraud mechanism, “locks” to the first User-Agent that registers on that account after a password reset.
This means that if are moving the trunk from a different PBX to 3CX, in order for it to work, you must reset your Deutsche Telefon account password as most likely it will be “locked” to the User-Agent of your previous system.
When configuring Deutsche Telefon SIP Trunks in 3CX, all numbers should be entered in a national number format (e.g. 05114740240), otherwise call routing will fail.
Outbound Caller ID
Deutsche Telefon Trunks support Clip No Screening which means you can present any number as outbound caller ID. These numbers can be in National, International or E164 format.
When configuring your Outbound Rules make sure that all numbers are dialed either in the National (e.g. 05114740240), International (e.g. 00495114740240) or E164 format (e.g. +495114740240). More information about how to create Outbound Rules and how they work can be found here.