1. First make sure that your VoIP fax connection (the line that you fax on) is set to G711. This is a non-compressed codec. G729 uses compression and will make the fax fail. Some providers have a “Bandwidth Saver” setting. This would be a compressed codec. Make sure this is Not enabled. If you do not have access to this setting call your provider and make sure your connection is set for G711.
2. Make the following changes:
- Slow down the transmission speed. Set the BAUD rate of the fax machine to 9600 bps or even lower (7200 bps would be the next slower setting). Refer to the following procedures for details on how to do so according to your fax machine. Sharp and Panasonic fax machines are set to 9600 by default or automatically fail back to it.
- Turn off or disable ECM (error correction mode), a setting, usually defaulted on, that many fax machines have. Refer to the following procedures for details on how to do so according to your fax machine.
3. Test faxing by using the HP Test Fax Service
You can use the following number to test your fax and get a response fax sent right back to you. Send a one page blank fax to 1-888-473-2963 (1-888-hpfaxme). After receipt of your fax, the test fax will generate a return back to you with acknowledgement that your fax was received. You should receive this fax within 5 minutes.
If you encounter communication errors or require other troubleshooting information please refer to the following article.