Backup system and fault detection and processing method

The invention relates to a backup system which comprises division point network access equipment, a third-generation (3G) communication module and a network management platform, wherein the division point network access equipment communicates with a core network through a main wired link, and supplies a network access function to a terminal; the 3G communication module is externally connected to an interface of the network access equipment or arranged in the network access equipment, and supplies a 3G wireless backup link to the division point network access equipment; and the network management platform is connected with the division point network access equipment through the main wired link and the 3G wireless backup link and used for monitoring states of the main wired link and the 3G wireless backup link. The invention also relates to a fault detection and processing method. According to the method, the 3G link is used as a backup of the wired link; compared with a mode of extra applying for a new wired l