The central processing module (CPM) is composed of the secondary power supply board (PWS), the alarm processing board (ALM), the main processing board (AMP), the central database board (CDP), the bus control board (BCP), and the built-in business processing board (ISP). The call connection management of the entire switching system is carried out by the central database board (CDP), which builds the central database (CDB) to manage trunk resources and various shared resources. At the same time, it also undertakes the maintenance management of the central module equipment. The AMP, CDP, and BCP hardware are all CPC boards, which achieve the functions of main control, central database management, and bus relocation by loading software, and operate in a master-slave mode. The CPM provides an interface between the main processor and the maintenance operation terminal, and cooperates with BAM to complete the OAM functions of the switching system. Among them, the AMP board and the BCP board are fixedly configured in pairs, the CDP board is configured at least in pairs, and the ISP board can be configured up to 6 pairs.