MFC-5840CN FAQs & Troubleshooting MFC-5840CN Not your product? Sort by: Updated Date Popularity 3 Results 1. 01/29/2014 I'm using Voice Over Internet Protocol (VoIP) and am having problems receiving faxes. 2. 05/10/2013 Why doesn't the machine answer when receiving a call? 3. 05/24/2006 I cannot receive a color fax. Why? Fax FAQs & Troubleshooting