Recommend:
To the knowledge base
Knowledge document #182
FRITZ!Box 7390
This support document is available for the following products:

Using the FRITZ!Box on an ISDN BRI

ISDN BRIs (point-to-point) are used in professional environments in conjunction with large telephone systems (PBXs). Point-to-multipoint ISDN lines are common in the private sector and small businesses. The FRITZ!Box is designed for use with point-to-multipoint lines.

If you set up the FRITZ!Box as described here, you can also use the FRITZ!Box and your ISDN telephone system on an ISDN BRI to make calls from the landline and over the internet. Since this is not a guaranteed product feature, AVM does not guarantee problem-free operation of the FRITZ!Box on an ISDN BRI.

Note:All instructions on configuration and settings given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

1 Connecting the FRITZ!Box to the point-to-point line and DSL

  1. Connect the longer gray end of the DSL/telephone cable (Y cable) included with delivery to the "DSL/TEL" socket on the FRITZ!Box.
  2. Connect the black end of the Y-shaped cable to the ISDN BRI.
  3. Connect the gray end of the Y-shaped cable to the DSL line.

2 Removing all devices and cables from the "FON S0" socket

  1. Remove all devices and cables from the "FON S0" socket on the FRITZ!Box.
  2. Do not connect the ISDN telephone system to the FRITZ!Box yet.

3 Enabling support for the point-to-point line in the FRITZ!Box

Preparations

  1. Configure the telephone so you can send keypad sequences (sequences of characters and numbers, such as *121#) and enter special characters such as * and # with it. On many telephones, you can configure this function in the menu "Operation at a PBX > Dialing options > Dial * and #".

Enabling support for the point-to-point line

  1. Enter #965*2*#91** on the telephone and press the call key (pick up the handset). This enables the function "point-to-point line with fixed TEI 0" in the FRITZ!Box.

    Note:You can enter #965*3*#91** to switch the FRITZ!Box back to "point-to-multipoint line with dynamic TEI".

4 Connecting a telephone system

  1. Connect the telephone system to the "FON S0" socket on the FRITZ!Box.

    Important:With the "point-to-point" operating mode, you can only connect one ISDN device to the "FON S0" socket.

5 Restarting the FRITZ!Box

When the FRITZ!Box is restarted, it recognizes that a telephone system designed for use on a point-to-point line is connected to its "FON S0" socket. After the restart, the FRITZ!Box automatically switches the "FON S0" socket to the "point-to-point" operating mode:

  1. Click "System" in the FRITZ!Box user interface.
  2. Click "Backup" in the "System" menu.
  3. Click on the "Restart" tab.
  4. Click the "Restart" button.

6 Configuring a trunk number and extensions in the FRITZ!Box

Enabling the landline settings

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephone Numbers" in the "Telephony" menu.
  3. Click on the "Line Settings" tab.
  4. Enable the option "Landline enabled".
  5. Click "Apply" to save the settings.

Configuring a trunk number and extensions

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephone Numbers" in the "Telephony" menu.
  3. Click the "New Telephone Number" button.
  4. Enable the option "Landline number" and click "Next".
  5. Enable the option "multiple landline numbers (ISDN line)" and click "Next".

    Important:You are only asked to select the type of landline (analog or ISDN line) when you configure the first landline number. If you want to change the connection type later, you must delete all of the landline numbers you configured first.

  6. In the field for the first ISDN number, enter the trunk number followed directly by the extension for the switchboard (without spaces).
  7. In the field for the second ISDN number, enter the trunk number followed directly by the longest internal extension (without spaces).
  8. Do not enter any additional telephone numbers if you want to connect all of your telephony devices to your ISDN telephone system.
    • If you also use other telephony interfaces on the FRITZ!Box (for example "FON 1" and "FON 2"), enter all of the extensions including the trunk number that you want to assign to devices connected to them. A maximum of ten extensions can be assigned to these interfaces, but your ISDN telephone system allows you to use more than ten extensions.
  9. Click "Next" and follow the wizard's instructions.

7 Configuring internet telephone numbers in FRITZ!Box

You can use internet telephone numbers with the "FON S0" socket if they correspond to the final digits of a trunk number with an extension (for example, 567 corresponds to the final digits of 4567) and/or they are not used by the internet telephony provider for registration. Other internet telephone numbers are not signaled to the "FON S0" socket if it is configured as a point-to-point line. You can use any internet telephone numbers for the other FRITZ!Box telephony interfaces (for example "FON 1" and "FON 2"):

Note:If an internet telephone number is used for registration, the telephone number must be transmitted to the internet telephony provider's SIP server during registration. Information on whether that is the case for a specific internet telephone number can be obtained from your internet telephony provider.

  1. Enter your internet telephone numbers in the FRITZ!Box. If you want to use an internet telephone number that is not contained in a trunk number with an extension for the "FON S0" socket, configure the internet telephone number in the FRITZ!Box as follows:
    1. "Other provider" must be selected from the "Telephony provider" drop-down list.
    2. Instead of entering the internet telephone number, enter the trunk number followed directly by an extension (without spaces) in the fields "Telephone number for registration" and "Internal Telephone Number in the FRITZ!Box".

      Note:This is possible because the telephone number is not used to log in with the internet telephony provider, and it is necessary so that the internet telephone number can be signaled at the "FON S0" socket.

    3. Enter the rest of the login information (for example username, password, registrar) that you received from your internet telephony provider.

8 Configuring the extensions of your telephone system

Now you can assign all of the telephone numbers you entered in the FRITZ!Box to the extensions of your telephone system. If you want to use an internet telephone number to make a call from an extension, enter the number in the extension exactly the way it is displayed in the FRITZ!Box user interface under "Telephony > Telephone Numbers".

You can also use all of the extension numbers of the point-to-point line with the extensions of your telephone system, even if you did not enter the extension numbers in the FRITZ!Box (see section "Configuring a trunk number and extensions in the FRITZ!Box").

9 Disabling the energy-saving mode in the FRITZ!Box

The FRITZ!Box is equipped with a number of energy-saving mechanisms. For example, communication between the internal S0 bus and ISDN devices is terminated when there are no active connections. Some ISDN devices have problems with this function. Therefore, disable this function in the FRITZ!Box if ISDN devices are having problems establishing connections:

Preparations

  1. Configure the telephone so you can send keypad sequences (sequences of characters and numbers, such as *121#) and enter special characters such as * and # with it. On many telephones, you can configure this function in the menu "Operation at a PBX > Dialing options > Dial * and #".

Disabling the energy-saving mode

  1. Enter #966*1* on your telephone and press the call key (pick up the handset).
  2. Hang up again after about 3 seconds.

    Note:You can re-enable this function by entering #966*0*.

Language selection