FRITZ!Box 6590 Cable Service - Knowledge Base

FRITZ!Box 6590 Cable Service

Cannot send or receive faxes with an external fax machine

Although the fax machine was configured according to our guide and you can conduct calls over the FRITZ!Box, you are either sometimes or never able to send or receive faxes. Faxes cannot be transmitted or transmission is aborted. One of the following error messages may be displayed in the event log of the FRITZ!Box:

  • "Not Acceptable Here (488)"
  • "Unsupported Media Type (415)"
  • "Not Acceptable Here (606)"

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

1 Checking the event log of the FRITZ!Box

  1. Click "System" in the FRITZ!Box user interface.
  2. Click "Event Log" in the "System" menu.
  3. Select "Telephony" from the drop-down list.
  4. Check whether one of the following error messages is displayed for the fax that failed. If so, note the information that correspond to the message.
  5. If the message "Unsupported Media Type (415) is displayed, your provider does not support the requested codec or generally does not allow fax transmission.
    • If the message "Not Acceptable Here (488 or 606)" is displayed, your provider does not support the T.38 standard. Without T.38, reliable fax transmission over the internet is not possible.

      Note:For fax reception, you can either use a telephone number from a provider that supports T.38 or disable T.38 again. T.38 may not be necessary for fax transmission.

2 Setting your fax machine to tone dialing

  1. Set your device to "tone dialing" (DTMF) and not "pulse dialing". If tone dialing is selected, you hear a tone when you press a number key; with pulse dialing, you hear clicking sounds. Information on how to set it up can be obtained from the device's manufacturer, for example refer to the manual.

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 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 machine is connected to when setting it up, another telephony device was already configured for the port. Delete that device.
  6. If the fax machine is connected to the "FON S0" socket 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.

4 Testing different remote sites

  1. Test fax transmission to or from different fax machines on different telephone lines.
  2. If fax transmission only fails with a particular remote site, the fax machine at the remote site is either not ready to receive faxes or incorrectly configured.

5 Testing different transmission speeds

Many fax machines allow you to select from various transmission speeds (4800, 7200, 9600, 14400 and 36600 baud):

  1. If possible with your fax machine, test the different transmission speeds one after the other. The FRITZ!Box supports transmission speeds of up to 14400 baud.

    Note:You can find information on configuring the transmission speed in its manual, or consult its manufacturer directly.

6 Enabling the error correction mode (ECM)

Using the error correction mode (ECM) on your fax machine can significantly improve the faxing results, as long as the remote machine also supports ECM. In some cases, however, the results may be worse:

  1. Enable the error correction mode (ECM) on your fax machine for testing purposes. Refer to the device's manufacturer for information on how to configure ECM, for example consult the manual.

7 Checking whether T.38 was used for fax transmission

  1. Click "Telephony" in the FRITZ!Box user interface.
  2. Click "Telephone Numbers" in the "Telephony" menu.
  3. Click on the "Voice transmission" tab. If the tab is not displayed, enable the Advanced View.
  4. Look for the aborted faxes under "Display table on completed telephone calls" and check whether "T.38" is displayed in the "Coding" column for these faxes:
  5. If "T.38" is displayed, T.38 was used for the fax transmission.
    • If "T.38" is not displayed, T.38 was not used. Without T.38, reliable fax transmission over the internet is not possible.

      Note:If your internet telephony provider does not support T.38, for the fax you can use an internet number of an internet telephony provider that supports T.38.