FRITZ!Fon MT-F – Service - Knowledge Base

FRITZ!Fon MT-F – Service

Caller ID is not shown for incoming calls

Caller ID is not shown on the display of your FRITZ!Fon when you receive a call:

  • The FRITZ!Fon does not show the caller ID.
  • The FRITZ!Fon briefly shows the number of the caller, and then only the bell icon is shown in the display and the number disappears.
  • The FRITZ!Fon does not show the number a caller has called.

Note:The configuration procedure and notes on functions given in this guide refer to the latest FRITZ!OS for your FRITZ!Box.

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

1 Activating text information in the FRITZ!Box

  1. Enter #960*2* on your telephone and press the call key (lift the receiver).
  2. Hang up again after about 3 seconds.

    Note:To deactivate the display of text information, enter #960*0*.

2 Assigning display names in the FRITZ!Box

The following step is only necessary if the telephone shows caller ID, but not the number that the caller called:

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephone Numbers" in the "Telephony" menu.
  3. Click the button (Edit) for the respective telephone number.
  4. Enter a name of your choice in the "Display name" field. If the field is not displayed, enable the Advanced View first.

    Example:
    You can enter "VOIP_12345", "provider_12345, "office", "private" or "12345" as the display name for the internet telephone number 12345.

  5. Click "OK" to save the settings.

3 Checking the FRITZ!Box's call list

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Calls" in the "Telephony" menu.
  3. Check which incoming calls (blue or red handset) caller ID is not shown for.
  4. If caller ID is not shown for calls to an ISDN or internet number, then either your telephony provider did not enable CLIP for your line, or the callers do not transmit their caller ID.
    • If caller ID is not shown for calls to an analog landline number, proceed with the following section.

4 Checking the analog telephone line and devices

The following step is only necessary if the caller ID is not shown when your analog landline number is called:

Checking whether the telephone and your line support CLIP

  1. Disconnect the FRITZ!Box from the DSL splitter's telephone socket.
  2. Connect an analog telephone to the DSL splitter's telephone socket.
  3. If the telephone does not show caller ID now, either your telephony provider did not enable CLIP for your line yet, your telephone does not support CLIP, or the caller did not transmit his caller ID.

Connecting all telephones and telephony devices to the FRITZ!Box

  • Connect all telephony devices (for example a telephone, fax) to the FRITZ!Box.

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

Testing whether another device is interfering with the FRITZ!Box

Interference from a device connected to the FRITZ!Box or the power mains may be reaching the FRITZ!Box. Therefore, perform the following test:

  1. Remove all devices and cables from the LAN ports and the USB port on the FRITZ!Box. If no devices are 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 other connected devices to the same electrical outlet.
    2. Test different electrical outlets and power outlet strips.
    3. Use UTP network cables to connect devices to the LAN ports on the FRITZ!Box. In contrast to STP network cables, for example the one included with delivery, UTP network cables do not have a ground wire and do not transmit interference to the FRITZ!Box.

      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, do not connect the device to the FRITZ!Box. Instead, connect it to a USB port on your computer.

Signal quality is too low

If your FRITZ!Box still does not show caller ID for incoming calls, the signal quality of your analog landline is too low.

Compared to simple telephones, PBXs always place higher requirements on the signal quality of analog telephone lines. The FRITZ!Box clearly surpasses the limitation of the specifications to correctly identify and process incoming signals. However, in the case of extremely interference-prone lines, the FRITZ!Box's tolerance to errors can be slightly lower than that of an analog telephone connected directly to your line. Therefore, under some circumstances, a telephone that is connected directly to your line can evaluate the CLIP information even though the FRITZ!Box cannot. This is not due to an error with the FRITZ!Box; instead, it is because the signal quality of the analog landline is too low.