FRITZ!Box 7390 Service - Knowledge Base

FRITZ!Box 7390 Service

Setting up an external fax in the FRITZ!Box

You can use a fax machine connected to an analog extension or the "FON S0" port of your FRITZ!Box to send and receive faxes over the Internet and/or your landline.

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

1 Enabling fax transmission with T.38

If you would like to use an Internet telephone number for faxing, then you must enable T.38 (fax over IP) for fax transmission in the FRITZ!Box. With T.38, a special network protocol is used for fax transmission instead of fax tones. As a result, transmission is significantly less susceptible to interference:

  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 on "Change connection settings" in the "Telephony connection" section. If the section is not displayed, enable the Advanced View first.
  5. Enable the option "Fax transmission using T.38".
  6. Click "Apply" to save the settings.

2 Enabling the fax switch (passive)

If you would like to use your analog landline number to receive telephone calls as well as faxes, enable the FRITZ!Box's fax switch. The fax switch automatically forwards faxes to a fax machine configured in the FRITZ!Box:

Important:In order for faxes to be recognized and forwarded, a different device, for example a telephone or answering machine, must accept the call first. The fax switch does not recognize calls that are not accepted.

  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. Enable the passive fax switch. If the setting is not displayed, enable the Advanced View first and configure your analog landline number in the FRITZ!Box. Then you can enable the passive fax switch.
  5. Click "Apply" to save the settings.

3 Reconfiguring the fax machine

Set up the fax machine in the FRITZ!Box, even if it is connected to the FRITZ!Box via an ISDN PBX:

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephony Devices" in the "Telephony" menu.
  3. If the fax machine is already displayed in the list of telephony devices, click the button (delete) 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 extension the fax device is connected to when configuring it, then another telephony device has already been configured for the extension. You must delete this device first.
  6. If the fax machine is connected to the "FON S0" port on the FRITZ!Box, during the configuration procedure you will be shown which telephone numbers to assign to the fax machine. If the fax machine is connected by means of an ISDN PBX, you must assign the telephone numbers to the extension of the ISDN PBX with the fax machine.