Abstract: The present invention discloses a multimedia message system, which includes: aSP; a Multimedia Message Service Center (MMSC), which is configured to receive, store and send multimedia messages; and a Multimedia Message Service Gateway (MMSG) connecting with at least one MMSC and the SP belonging to the MMSG respectively, which serves to authenticate the SP and a user in the multimedia message and a provided service, and to send the multimedia messages from the SP or the MMSC. And the present invention provides three methods for sending multimedia messages. The system and methods provided by the present invention can lower the load of the MMSC and enhance the security of the MMSC.

Abstract: A method for changing ICS session media includes: receiving a media type change request including a new media type sent from a terminal equipment or a MSC, releasing a CS call leg based on an original media type between an ICCF and the terminal equipment, establishing a CS call leg based on the new media type between the ICCF and the terminal equipment, and updating a media type of a second call leg between the ICCF and a second party into the new media type; or, receiving a media type change request including a new media type sent from a second party, updating a media type of a second call leg between an ICCF and the second party into the new media type, releasing a CS call leg based on an original media type between the ICCF and a terminal equipment, and establishing a CS call leg based on the new media type between the ICCF and the terminal equipment.