FRITZ!Box 7583 Service - Knowledge Base

FRITZ!Box 7583 Service

DSL data rate is too low

The DSL data rate displayed in the FRITZ!Box user interface is significantly lower than the DSL speed guaranteed by the DSL provider.


  • The data rate of the DSL connection primarily depends on the length and quality of the access line. Faults in the cabling or problems with the internet service provider's exchange (DSLAM) can also affect it.

    Important:With many DSL lines, you will not be able to fully achieve the guaranteed throughput. This is why DSL providers say that they offer DSL speeds of "up to" a certain value.

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 Checking the maximum throughput

The DSL provider sets a maximum achievable throughput for each DSL line. The speed that can actually be achieved on your DSL line cannot be higher than the maximum throughput:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "DSL Information" in the "Internet" menu.
  3. Click on the "DSL" tab.
  4. Check the "Max. DSLAM throughput" line to see the maximum data rate set for your line.
  5. If your DSL provider guaranteed you a higher throughput, contact your DSL provider.

2 Checking the cabling

Errors in the cabling often go unnoticed, but it can significantly reduce the DSL data rate. Therefore, check the wiring in your home:

  1. Remove the DSL splitter if you are using the FRITZ!Box on an IP-based connection.
  2. Remove all cable extensions, unused cables, telephone jacks, and additional electrical components (for example surge protection, automatic extension outlets).
  3. Make sure that the FRITZ!Box is correctly connected to your DSL line. You will find detailed instructions on the installation poster included with the FRITZ!Box and in the manual.

3 Installing the latest FRITZ!OS for the FRITZ!Box

Installing the latest FRITZ!OS makes your FRITZ!Box compatible with the latest DSL technology used by DSL providers in their DSL exchanges:

  1. Install the latest FRITZ!OS on the FRITZ!Box.

4 Resetting the interference resistance

Set all of the controls on the "Interference Resistance" ("Line Settings") tab to "Maximum Performance" since other settings can cause a reduction in DSL data rate:

  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. If the tab is not displayed, enable the Advanced View.
  4. Click the "Reset Setting" link.
    • Now the interference resistance is automatically set to "Maximum Performance".

5 Checking the data rate with a different DSL modem

With many DSL lines, you will not be able to fully achieve the maximum throughput guaranteed by your DSL provider. To check whether the FRITZ!Box's data rate is limited by your line or whether there is a technical problem, use a different DSL modem to test the throughput:

  1. Disconnect the FRITZ!Box from the DSL line.
  2. Connect a different DSL modem to the DSL line.
  3. Test which data rate you achieve with the other DSL modem. Test the other modem soon after you finish testing the FRITZ!Box to ensure that you test it under the same conditions.
  4. If the data rate you achieve with the other modem is also significantly lower than the throughput agreed on with your DSL provider, have your provider check your line.

    ATTENTION!You may be charged for checking. Ask your provider about charges in advance!