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Knowledge document #3294

Since updating FRITZ!OS, the FRITZ!Box's Power LED flashes

Since updating FRITZ!OS, the FRITZ!Box can no longer establish a DSL connection. The FRITZ!Box's Power/DSL LED flashes continuously since the update and the following error message is displayed in the event log of the FRITZ!Box:

"DSL not responding (no DSL synchronization)"

Since updating FRITZ!OS, the FRITZ!Box can no longer establish a DSL connection. The FRITZ!Box's Power LED flashes continuously since the update and the following error message is displayed in the event log of the FRITZ!Box:

"DSL not responding (no DSL synchronization)"

Simply proceed as described below. After each measure, check whether the problem is solved.

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

1 Restarting the FRITZ!Box

  1. Unplug the FRITZ!Box for 5 seconds.

    Note:The FRITZ!Box settings are retained when you unplug it. The restart takes about 2 minutes. During this time, you cannot access the FRITZ!Box.

2 Checking the event log of the FRITZ!Box

  1. Click "System" in the FRITZ!Box user interface.
  2. Click "Event Log" in the "System" menu and then "Internet Connection".
  3. If the message "DSL is available (DSL synchronization exists with [...] kbit/s)" is displayed in addition to the message "DSL not responding", follow the steps in our guide FRITZ!Box reports that the DSL connection drops frequently.

3 Resetting the interference resistance

Set the interference resistance for the DSL connection to "maximum performance" since otherwise you will not be able to establish a DSL connection with some DSL lines:

Note:The interference resistance of your DSL connection should only be changed if you occasionally experience problems with the DSL connection.

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "DSL Information" in the "Internet" menu.
  3. Click on the "Interference Resistance" ("Line Settings") tab.
  4. Click "Interference Resistance Settings" to display all of the settings.
  5. Click "Reset Setting" and confirm with "OK" to configure the DSL connection for maximum performance.

4 Using the previous DSL version

The DSL version of the FRITZ!Box undergoes constant development with each FRITZ!OS to ensure that it can establish optimal DSL connections under all circumstances. In individual cases (for example on DSL lines with outdated DSLAMs) the FRITZ!Box may only be able to establish a DSL connection with certain DSL versions. Therefore, enable previous DSL version:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "DSL Information" in the "Internet" menu.
  3. Click on the "Interference Resistance" ("Line Settings") tab.
  4. Click "Interference Resistance Settings" to display all of the settings.
  5. Enable the option "Use previous DSL version".
  6. Click "Apply" to save the settings.
  7. Now the FRITZ!Box enables the previous DSL version and then restarts. The restart will take about two minutes.

Important:If the FRITZ!Box still cannot establish a DSL connection with the previous DSL version, follow the steps in our guide FRITZ!Box's Power LED flashes.

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