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Poor voice quality when conducting calls

When conducting calls, one of the following issues either occasionally occurs or always occurs:

  • When conducting calls, you experience disturbances such as echo, dropouts, delays or background noise.
  • A loud and annoying hiss is heard when conducting calls. 
  • The voice of one or both parties sounds distorted or "choppy".

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

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

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

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

2 Restarting the FRITZ!Box

  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.

3 Checking the DSL connection for errors

A bad DSL connection has the greatest impact on applications that require real-time transmission, such as internet telephony. It especially affects upload, thus affecting the quality of voice data being transmitted to the party being called. Therefore, check whether the quality of the DSL connection is sufficient for conducting internet calls:

  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 in the section "Error Counter" whether "Not Remediable Errors" (CRC) occur in the FRITZ!Box or the DSL exchange while you conduct a call over the internet.
  5. If no errors occur, continue with the next section. The signal quality is sufficient for conducting internet calls.

4 Configuring FRITZ!App Fon for Android

The following steps are only necessary if the problem occurs with FRITZ!App Fon on an Android device:

  1. Start FRITZ!App Fon.
  2. Tap "More" and then "Settings".
  3. Tap the menu key on the telephone and then tap "Advanced".
  4. Adjust the microphone volume gradually.

5 Configuring the FRITZ!Box for internet telephony

Setting the speed of the line

The following step is only necessary if the FRITZ!Box is not connected directly to a DSL line:

Note:When used as a DSL router (standard), the FRITZ!Box determines these values automatically.

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "Account Information" in the "Internet" menu.
  3. Click "Change Connection Settings".
  4. Enter the speeds of your internet connection in the "Upstream" and "Downstream" fields in the section "Connection Settings".

    Enter 2000 for an upstream of 2 Mbit/s; enter 32000 for a downstream of 32 Mbit/s.

  5. Click "Apply" to save the settings.

Setting up a prioritization rule for internet telephony

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "Filters" in the "Internet" menu.
  3. Click on the "Prioritization" tab.
  4. Check if there is a rule for "Internet telephony" under "Real-Time Applications".
  5. If there is no rule, click "New Rule".
  6. Select "All devices" (default) as the network device from the drop-down list.
  7. Select "Internet telephony" from the drop-down list "Enter the network application:".
  8. Click "OK" to save the settings.

Configuring other applications

Applications such as file sharing software and online games establish many simultaneous internet connections. Although the "Traffic Shaping" function of the FRITZ!Box ensures that voice data is prioritized and evenly transmitted, for technical reasons it can only compensate for disturbances caused by these applications to a limited extent. This is why many applications offer the following setting options:

  1. Decrease the number of simultaneous connections allowed by the application.
  2. Reduce the maximum throughput available in the application..
  3. If you still experience problems or the application does not offer these settings options, configure the application as a background application in the FRITZ!Box.

The FRITZ!Box's echo compensation and traffic shaping functions guarantee high voice quality. However, if you still experience an echo, delays or short dropouts, they are caused by the telephone, your internet service provider or telephony provider, and cannot be influenced by the FRITZ!Box.