MFC-4800 FAQs & Troubleshooting MFC-4800 Not your product? Sort by: Updated Date Popularity 2 Results 1. 15/12/2014 I am using Voice Over Internet Protocol (VoIP) and cannot send and/or receive faxes. What can I do? 2. 10/05/2013 Why doesn't the machine answer when receiving a call? Fax FAQs & Troubleshooting