To the knowledge base
Knowledge document #123

Humming noise when conducting calls on an analog telephone line

During calls over the analog landline, either the party using the FRITZ!Box to call or both parties hear a deep humming sound. The noise is clearly audible and is not the very quiet and barely audible noise that can be heard on all analog landlines. You do not hear the humming noise during internet calls.

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

1 Checking the landline

  1. Disconnect the FRITZ!Box from the landline.
  2. Connect a telephone to the same line.
  3. If the telephone also does not work when connected to the line, contact your telephony provider and have your line checked.

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

2 Connecting all telephones and telephony devices to the FRITZ!Box

  1. Connect all telephony devices (for example telephones, faxes) to the FRITZ!Box.

    Important:Connecting additional telephony devices or sockets to the telephone jack can cause errors.

3 Turning off other base stations

  1. For testing purposes, turn off other base stations in the vicinity of the FRITZ!Box.
  2. If the problem no longer occurs then, place the base station farther away from the FRITZ!Box.

    Note:As an alternative, you can register your cordless telephones directly with the FRITZ!Box and not use the additional base station.

4 Excluding another device as source of interference

Either a device connected to the FRITZ!Box or the power mains may be transmitting interference to the FRITZ!Box. Perform the following test to see if this is the case:

  1. Remove all devices and cables from the LAN ports and the USB port on the FRITZ!Box. If no devices were connected, connect a computer to a LAN port on the FRITZ!Box.
  2. If the error no longer occurs, then a device connected to the FRITZ!Box was transmitting interference to the FRITZ!Box or the computer now channels it off. Usually, you can eliminate the cause of the interference through one of these measures:
    1. Use a power strip to connect the FRITZ!Box and all of the connected devices to the same electric outlet.
    2. Test different electric outlets and power strips.
    3. Use UTP network cables to connect devices to the LAN ports on the FRITZ!Box. UTP network cables do not have a ground wire and do not transmit interference to the FRITZ!Box, unlike STP network cables such as the one included with delivery.

      Important:If the problem occurs with a FRITZ!Powerline adapter, use the UTP network cable included with the FRITZ!Powerline adapter.

    4. If a device connected to the USB port is transmitting interference to the FRITZ!Box, connect the device to a USB port on your computer instead of to the FRITZ!Box.

If the humming is still present, the issue is not caused by the FRITZ!Box. Instead, it is caused by a different component (such as a telephone, cable, power supply).