FRITZ!Box 7590 Service - Knowledge Base

FRITZ!Box 7590 Service

Setting up an external fax in the FRITZ!Box

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

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

1 Enabling fax transmission with T.38

If you use an internet telephone number for faxing, you must enable T.38 (fax over IP) in the FRITZ!Box for fax transmission. With T.38, a special network protocol is used for fax transmission instead of signal tones. This makes transmission 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 "Changing the Settings" in the "Telephony connection" section. If the section is not displayed, enable the Advanced View.
  5. Enable the option "Fax transmission using T.38".
  6. Click "Apply" to save the settings.

2 Enabling the fax switch (passive)

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

Important:For faxes to be recognized and forwarded, a different device, for example a telephone or answering machine, must accept the call. 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 and configure your analog landline number in the FRITZ!Box. You can then 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 (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 machine is connected to when configuring it, another telephony device was already configured for the port. Delete that device.
  6. If the fax machine is connected to the "FON S0" port on the FRITZ!Box, during setup you will be shown which telephone numbers to assign to the fax machine. If the fax machine is connected via an ISDN PBX, you must assign the telephone numbers to the port on the ISDN PBX that the fax machine is connected to.