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  • Setting up a Snom DECT Base on a FritzBox



To anticipate this, a FritzBox can easily act as a SIP Registrar.
This article is based on a test on a FritzBox 7390 or 7590. It was tested on a Telekom All-IP connection.

1) Connecting FritzBox to DSL

The cables and adapters supplied with the FritzBox differ depending on the product variant. Therefore, take the cabling according to the scope of delivery of your FritzBox as in one of the two following sections described above.

Connect FritzBox to DSL via DSL cable (TAE/RJ45)

  1. Plug the RJ45 plug of the DSL cable into the "DSL/TEL" socket of the FritzBox.

  2. Plug the TAE plug of the DSL cable into the socket of the TAE socket labeled "F" (see Fig. 1). 

Connecting FritzBox to DSL via DSL adapter

  1. Plug the long end of the DSL/telephone cable into the "DSL(/TEL)" socket of the FritzBox.
  2. Insert the short grey cable end into the grey DSL adapter.
  3. Plug the DSL adapter into the socket of the TAE socket labeled "F".
  4. Leave the black cable end free (see illustration).

2) Setting up Internet access

  1. Call up the FritzBox user interface in your internet browser of choice (Firefox, Chrome, IE). The user interface can be accessed either via or the IP address of the FritzBox (in the factory settings In addition, the FritzBox can always be reached via the emergency IP
  2. If the wizard for Internet access does not start automatically, click on "Wizard", and then click on "Set up Internet access".

  3. Select "Telekom" in the combo box and click "Next". If "Telekom" cannot be selected, first select "Other Internet providers" and then "Telekom".

  4. Enter the access data you have received from Telekom in the respective input fields and click "Next".

  5. Activate the option "Check Internet connection after saving the settings" and click "Next".

  6. Now the FritzBox establishes the Internet connection with the entered access data.
    The setup is complete when the message "Internet connection verification successful" is displayed.
    Afterwards you will find your access data under the menu item: Internet/Access data

3) Setting up Snom IP-Phone

The configuration of the Snom phone on the FritzBox is relatively simple. First you have to create a new telephony device in the FritzBox - type is IP phone.

The user name and password are important here.

  • The user name should have at least 8 characters and will be used later when configuring the Snom phone.
  • The password must have exactly 8 characters, no more and no less.

You should only allow registration from the Internet if you really need it. This is not necessary for an IP phone behind the Fritz Box and should therefore remain deactivated for security reasons.

3.1) Step by step instructions - FritzBox:

  • Click on "Telephony" in the menu on the left and select "Telephony device".
  • Click on the far right point: "Set up new device".

Since the desired telephone (with and without answering machine) is already selected by default, simply click on "Next" on the far right here.

  • Next select the item: "LAN/WAN (IP phone)".
  • Name the new phone with a unique name.
  • Then click on "Next" again.

  • Now assign a "user name" and a "password". (The assigned phone number can also be used as user name if you want.)
  • Then click on "Next".

  • The user name should have at least 8 characters.
  • The password must have exactly 8 characters, no more and no less.

  • Select the phone number you want to use for outgoing calls.
  • Then click on "Next"

  • Now select the phone number under which the new telephone is to be reached (usually the same phone number as the outgoing number).
  • Then click on "Next"

  • Check in the summary if everything looks correct.
  • Then click on "Next".

  • To complete the process, a "popup window" will appear asking you to do this with an existing telephone 
    to confirm the legality of the setup process. This prevents external users from misusing your FritzBox for their own purposes.
  • If you don't have another phone just press the FritzBox button on your FritzBox. (See link in popup window).

  • Once the process has been successfully completed, you will receive another "Popup Window" as confirmation.

  • After successful setup, the new Snom Phone should now be available under "Telephony Devices", and can be configured there at any time. 

3.2 Step by step guide - Snom DECT base:

With the setup of the Fritzbox most of the setup is done. Now you only have to set up the DECT base.

How do I get into the web user interface of a Snom DECT base M-Series
  • Since automatic provisioning is not supported by the Fritzbox, the Snom DECT base must be set up via your web user interface (WUI). To access the base, enter the IP address of your phone in your Internet browser (e.g. How to find out the IP address of your base is described in the following article: How to enter M300, M700, M900 - Web Interface

Configure server: 

  • First select the menu item "Servers" on the left side and assign a name of your choice at "Server Alias" and then enter the IP address of your Fritz.Box at "Registrar".
  • Then save it at the bottom of the page.

Configuring an extension

  • Now switch to the menu item "Extensions" and create a user.
  • Now click on "Add extension".

  • Now enter the following values:
    Line name: e.g. the Fritzbox internal extension
    Extension: snomphone (Account name you have created in the Fritzbox for the device)
    Authentication User Name:  (See Extension)
    Display Name: here you can assign a display name

  • Then save.

More information on how to add an extension to a Snom DECT base of the M series can be found here: DECT - 3.1 Add Extensions

For direct configuration of a snom phone on any other router (without SIP registrar feature) on a telecom line they need a different configuration:

For a standard All-IP connection of the Telekom it is the following :

  • User name: (telephone number with area code)
  • Password corresponds to PPPoE password
  • Registrar:
  • Outboundproxy:;transport=tcp (Mostly optional)
  • If required a STUNS server (optional) = Stunserver:

Setting up Telekom SIP trunk (FritzBox)

The FRITZ! box supports only the operating mode "Registered Mode". The "Static Mode" is not supported.
To use this new feature (sip trunk) a lab version is currently required.

  1. Click on "Telephony" in the FritzBox user interface.
  2. Click on "Own numbers" in the "Telephony" menu.
  3. Click on the "New phone number" button.
  4. Activate the option "Internet number" and click "Next".
  5. Select "Telekom SIP trunk" in the combo box.
  6. Enter the master number of the connection.
  7. Select the length of the longest internal extension from the combo box.
  8. Enter the extension number of the interrogation center.
  9. Enter the other phone numbers of your SIP trunk. You can enter up to 19 additional phone numbers,
     which you can use for telephones and other devices on the FRITZ! box.
    Unregistered numbers can only be used on an ISDN telephone system for a system connection,
    connected to the "FON S0" port.
  10. Enter your user name and password in the "Access data" section.
  11. Click on "Next" and follow the instructions of the wizard.

Now you can assign the phone numbers of your SIP trunk to telephones and other devices.