MMS is the MultimediaMessagingService of China Unicom. Its biggest feature is that it supports multimedia functions and can transmit comprehensive content and information, including text, images, sounds, data and other multimedia formats. Technically speaking, MMS is not a short message, but with the support of GPRS network and WAP wireless application protocol as the carrier to transmit pictures, sounds, words and other information. MMS service can realize instant multimedia information transmission from mobile phone end to end (including sending to domestic mobile users), from mobile phone terminal to Internet or from Internet to mobile phone terminal.

Peer-to-peer short message service refers to the short message transmission from mobile phone to mobile phone. Among them, peer-to-peer SMS in the network refers to sending messages to each other between Unicom users, and peer-to-peer SMS outside the network refers to sending messages to each other between Unicom users and other network users.