FAX-2580C FAQs & Troubleshooting FAX-2580C Not your product? Sort by: Updated Date Popularity 3 Results 1. 05/15/2013 I am using Voice Over Internet Protocol (VoIP) and I'm having problems sending faxes. 2. 04/25/2013 I am experiencing problems sending a fax. 3. 06/18/2012 I'm using MagicJack and am having problems sending or receiving faxes. Fax FAQs & Troubleshooting