FRITZ!Box 6810 LTE Service - Knowledge Base

FRITZ!Box 6810 LTE Service
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Integrated fax transmission fails occasionally or always fails

Although you configured the internal fax according to our guide, fax transmission either fails occasionally, or it always fails. You either cannot send faxes at all, or they are incomplete. When faxing fails, one of the following error messages may be displayed, or one of the following error messages may be displayed in the event log of the FRITZ!Box:

  • "Transmission failed [0x3301]."
  • "Transmission failed [3495]."
  • "Transmission failed (0x3490)."
  • "An error occurred while sending a fax. Fax transmission was unsuccessful or incomplete."
  • "An error occurred. Error description: Fax transmission failed. Please enter your data again. If the error occurs again, please consult AVM Support."
  • "Not Acceptable Here (488)"
  • "Unsupported Media Type (415)"
  • "Not Acceptable Here (606)"

Important:Some of the settings described here are only displayed if the advanced view is enabled in the user interface. The configuration procedure and notes on functions given in this guide refer to the latest FRITZ!OS

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

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. Enable the option "Fax transmission using T.38" in the "Voice Packets" section.
  5. Click "Apply" to save your settings.

2 Entering your location information

  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. Select your country from the drop-down list under "Location Information". If your country is not included in the list, select "Other country".
  5. For the "Country code", enter the country code prefix in the first field and the country code in the second field (for example for Germany "00" and "49", see fig.).
  6. For the "Area code", enter the area code prefix in the first field and the area code in the second field (for example for Berlin "0" and "30", see fig.).

    Fig.: Entering the country code and area code (e.g. for Germany and Berlin)

  7. Click "Apply" to save your settings.

3 Using a different web browser

The issue may be caused by the web browser (for example plug-ins may be interfering):

  • Test a different web browser (for example Chrome, Firefox) and make sure that you are using the current version of the browser.

4 Testing fax transmission to various remote fax machines

  • Test whether you can send a fax to or from different fax machines connected to different telephone lines.
    • If fax transmission only fails with a particular line, then the fax machine at the remote site is either not ready to receive faxes or incorrectly configured.

5 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. Click on the "Telephony" tab.
  4. Check whether one of the following error messages is displayed in the event log after faxing fails, and note the corresponding information:
    • "Unsupported Media Type (415)"
      • Your Internet telephony provider does not support a requested codec or does not allow fax transmission as a rule.
    • "Not Acceptable Here (488)" or "Gewünschter Rufaufbau wird nicht unterstützt (606)"
      • Your Internet telephony provider does not support the T.38 standard. Without T.38 (Fax over IP), fax transmission over the Internet is not reliable.
        • Disable T.38 in the FRITZ!Box user interface. You may be able to send and receive faxes without using T.38.

          Note:If you cannot send and receive faxes without using T.38, then you can use an Internet number of an Internet telephony provider that does support T.38 for faxing.

6 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.
  4. Look for aborted faxes under "Display table on completed telephone calls" and check whether "T.38" is displayed in the "Coding" column for these faxes:
    • If "T.38" is displayed:
      • The standard T.38 was used for this fax transmission.
    • If "T.38" is not displayed:
        The standard T.38 was not used for this fax transmission. Your Internet telephony provider must support the T.38 standard. Without T.38 (Fax over IP), fax transmission over the Internet is not reliable.

      Note:If your Internet telephony provider does not support T.38, then you can use an Internet number of an Internet telephony provider that does support T.38 to receive faxes.