FRITZ!Box 6840 LTE Service - Knowledge Base

FRITZ!Box 6840 LTE Service

Configuring a combined telephone/fax machine in the FRITZ!Box

You can connect a combined telephone/fax machine to an analog extension on the FRITZ!Box and use it to send faxes and make telephone calls.

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

1 Configuring a combined telephone/fax machine

Configure the combined telephone/fax machine as a fax machine in the FRITZ!Box:

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephony Devices" in the "Telephony" menu.
  3. If the fax machine already exists in the list of telephony devices, click the (Delete) button for the fax machine.
  4. Reconfigure the fax machine: Click the "Configure New Device" button and follow the instructions.
  5. If you cannot select the port the fax device is connected to when setting it up, another telephony device has already been configured for that port. Delete that device.

2 Disabling fax transmission with T.38

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephone Numbers" in the "Telephony" menu.
  3. Click on the "Line Settings" tab.
  4. Click "Changing the Settings" ("Change connection settings") in the "Telephony connection" section.
  5. Disable the option "Fax transmission using T.38" in the "Voice Packets" section. If the section is not displayed, enable the Advanced View.

    Note:The T.38 standard (Fax over IP) allows reliable fax transmission over the internet. However, when T.38 is enabled, you cannot use the combination device to conduct calls over the internet. When faxing over the internet without T.38, faxes may not be transmitted properly.

  6. Click "Apply" to save the settings.
    • If you cannot send faxes without T.38, re-enable the option "Fax transmission using T.38". If you are then able to send faxes, either leave T.38 enabled and only use the combination device for faxing, or disable T.38 and only use the combination device for conducting calls.