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Telephone connected to FRITZ!Box rings, but there is no incoming call

Occasionally a telephone connected to the FRITZ!Box rings although no one called you, or it rings right after you have ended a call and hung up. Sometimes the telephone may continue to ring although the caller already hung up before you could answer the telephone. When you pick up the handset, you hear a dial tone.

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 Disabling the option "Message waiting indication on the telephone (MWI)"

The following steps are only necessary if the telephone is connected to the analog extension "FON":

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephony Devices" in the "Telephony" menu.
  3. Click the (Edit) button for the respective telephone.
  4. Click on the "Telephony Device Features" tab.
  5. Disable the option "Message waiting indication on the telephone (MWI)".
  6. Click "OK" to save the settings.

If the telephone no longer rings now, you have new messages in the mailbox of your landline telephony provider or internet telephony provider. The FRITZ!Box calls you to indicate that you have new messages because your telephony provider supports MWI (Message Waiting Indication).

2 Disabling the alarm

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Alarm" in the "Telephony" menu.
  3. Disable the alarm.
  4. Click "Apply" to save the settings.

3 Checking the cabling

If you are using the FRITZ!Box on an IP-based line without a conventional analog or ISDN landline, do not plug in the end of the Y-shaped cable for landline. Otherwise, interference is transmitted to the FRITZ!Box:

  1. Check whether the black end of the Y-shaped cable is plugged in somewhere. If so, unplug the cable.

4 Checking the analog telephone line and devices

The following steps are only necessary if the FRITZ!Box is connected to an analog landline:

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.

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, a device connected to the FRITZ!Box was transmitting interference to the FRITZ!Box or the computer now channels it off. Normally, one of the following measures eliminates the cause of the interference:
    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.

Signal quality is too low

If telephones connected to the FRITZ!Box continue to ring although there is no incoming call, the signal quality of your analog landline is too low.

Compared to simple telephones, PBXs always place higher demands on the signal quality of analog telephone lines. The FRITZ!Box is capable of recognizing and processing all incoming signals correctly well beyond the specification limits. However, when used on lines subject to much interference, the FRITZ!Box's tolerance to errors is slightly lower than that of an analog telephone connected directly to your line.