FAQs & Troubleshooting FAQ Search Results FAX-2580C Not your product? Search by FAQ ID number Search Back to FAQs & Troubleshooting. 2 Results 1.faq00002123_003 I am using Voice Over Internet Protocol (VoIP) and I'm having problems sending faxes. 2.faq00002123_018 I am using Voice Over Internet Protocol (VoIP) and I'm having problems receiving faxes. FAQs & Troubleshooting
