https://app.knowbase.one/vault/rfc/docid/3191
RFC2879: Content Feature Schema for Internet Fax (V2)
Network Working Group G. Klyne Request for Comments: 2879 Content Technologies Obsoletes: 2531 L. McIntyre Category: Standards Track Xerox Corpor...
https://app.knowbase.one/vault/rfc/docid/3193
RFC2880: Internet Fax T.30 Feature Mapping
Network Working Group L. McIntyre Request for Comments: 2880 Xerox Corporation Category: Informational G. Klyne Content Technologies ...