FRITZ!Box 6840 LTE – Service - Knowledge Base

FRITZ!Box 6840 LTE – Service

Poor speech quality when making and/or receiving telephone calls

One of the following issues sometimes or always occurs when you conduct calls:

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

Important:Some of the settings described here are only displayed if the advanced view is enabled in the user interface. The configuration procedure and notes on functions given in this guide refer to the latest FRITZ!OS

Simply proceed as described below. After each measure, check whether the issue persists.

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

2 Installing the latest software for your telephone

The following steps are only necessary if you are using a FRITZ!Fon:

3 Excluding repeater(s) as a source of interference

The following steps are only necessary if you use one or more repeaters to increase the DECT range of the FRITZ!Box and the background noise occurs when making calls with cordless telephones:

  1. Unplug all of the repeaters.
  2. Check whether you hear background noise when you make a call with a cordless telephone while you are close to the FRITZ!Box.
    • If you no longer hear background noise, the repeater is either not properly connected with the FRITZ!Box or it is not positioned correctly:
    • If you can still hear background noise:
      1. Plug the repeater in again.
      2. Proceed with the following section.

4 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.

5 Finding the ideal location for the FRITZ!Box

You can use the alignment aid to find the ideal location for the FRITZ!Box and the best position for the LTE antennas:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "LTE Information" in the "Internet" menu.
  3. Click on the "Reception" tab.
  4. Click the "Start Alignment Aid" button.
    • Now the FRITZ!Box shows the signal strength for both LTE antennas.

      Note:When the alignment aid is active, the current signal strength is also displayed in a five-level display on the FRITZ!Box LEDs. This means that you can also find the best location for the FRITZ!Box without using the FRITZ!Box user interface.

  5. Select a location for the FRITZ!Box where the value shown is as high as possible. When doing so, note the following:
    • Do not set up the FRITZ!Box in the corner of a room.
    • Position the FRITZ!Box as close to an outside wall as possible. If you know where your provider's LTE radio cell is located, position the FRITZ!Box by the wall facing the LTE radio cell.

      Important:If the FRITZ!Box is located in the attic or on a window sill, make sure that the permissible operating temperature of 0° to 40° Celsius is not exceeded.

    • Position the FRITZ!Box so that it is as unobstructed as possible, i.e. not directly in back of or under an obstacle (for example pieces of furniture, heater).
    • Position the LTE antennas of the FRITZ!Box so that they are as perpendicular as possible (90° angle). For example, position one antenna vertically and the other horizontally.

6 Checking the quality of your LTE connection

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

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "LTE Information" in the "Internet" menu.
  3. Click on the "LTE" tab.
  4. Check which "SINR" and "RSRP" values are shown for the the FRITZ!Box's "Antenna 1" in the "Antenna Signal and Connection Quality" section:
    • If the SINR values are positive and the RSRP values are better than -105, then the signal quality of the LTE connection is sufficient for conducting Internet calls.

      Example:
      If the SINR value is 10 and the RSRP value is -95, the poor speech quality you are experiencing is generally not due to the LTE connection.

      • Proceed with the following section.
    • If the SINR values are negative and the RSRP values are lower than -105, the poor LTE signal quality may lead to disturbances when conducting calls over the Internet.

      Example:
      If the SINR value is -3 and the RSRP value is -115, the poor speech quality you are experiencing is generally due to the LTE connection.

      If you are using your FRITZ!Box in the outdoor coverage area of your LTE provider or in buildings with a strong shielding effect due to structural conditions or the surrounding environment, the internal antennas may not be sufficient to guarantee an optimum LTE connection:
      • Connect an outdoor LTE antenna to the FRITZ!Box.

        Note:If you are using your FRITZ!Box outside of the outdoor coverage area of your LTE provider, external antennas may also not be sufficient to guarantee an optimum LTE connection.

7 Reducing the in-call volume on the telephone

  • Reduce the in-call volume on the telephone.

    Note:If you would like to reduce the in-call volume on your FRITZ!Fon, press the "down arrow" or "telephone book" icon on the control ring while speaking on the telephone.

8 Registering cordless telephones with the FRITZ!Box

  • Register all cordless telephones with the FRITZ!Box's base station and switch off all other base stations.

9 Restoring FRITZ!Fon to its factory settings and re-registering it

The following steps are only necessary if the issue only occurs with a particular FRITZ!Fon, and you do not experience problems with speech quality when using other telephones:

Restoring the telephone to its factory settings

  1. Press the "Menu" key on the telephone.
  2. Scroll to "Settings" and press "OK".
  3. "Reset" > "OK" > "OK"

Deleting the telephone

  1. Click "DECT" in the FRITZ!Box user interface.
  2. Click "Cordless Telephones" in the "DECT" menu.
  3. Click the button (Delete) to delete the relevant telephone.

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.

Re-registering the telephone

10 Configuring FRITZ!App Fon for Android

The following steps are only necessary if the issue occurs when using FRITZ!App Fon with an Android device:

Enabling alternative microphone

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

Adjusting the microphone volume

  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 step by step.

11 Configuring the FRITZ!Box for Internet telephony

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 under "Real-time Applications" whether a rule for "Internet telephony" is present.
  5. If there is no rule for Internet telephony, click "New Rule".
  6. Select "All devices" (default) as the network device from the corresponding drop-down list.
  7. Select the entry "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 certain extent:

  1. Decrease the number of simultaneous connections that are allowed.
  2. Reduce the maximum throughput available to the application.
    • If you still experience disturbances when conducting calls over the Internet:

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