2002-08-08 2004-10-26 RFC Required fax-message Indicates a message whose primary content is a fax mail message. The primary content is image data. The context is usually a message recorded from a facsimile telephone call. multimedia-message Indicates a message whose primary content is a multimedia message. The primary content is multimedia, most likely MHTML. The context is often spam or newsletters. None Indicates an unknown message context. pager-message Indicates a message whose primary content is a page. The primary content is text data. The context is an urgent message usually of a limited length. text-message Indicates a classic, text-based, Internet message. video-message Indicates a message whose primary content is a video mail message. The primary content is video data. The context is usually a message recorded using a video camera, or a message whose primary purpose is to contain an external reference to a message recorded using a video camera. voice-message Indicates a message whose primary content is a voice mail message. The primary content is audio data. The context is usually a message recorded from a voice telephone call.