Multi-user expansion system

This invention relates to phone and data communication system user extension method and discloses a multi-user extension system, which comprises main machine frame and second machine frame, wherein the main machine frame comprises operation board module and main control process board module and the second machine frame comprises second operation board module. The main control process board module is connected with main machine operation board module through backboard or panel of the main machine frame and is used to manage the main machine frame operation board module and second frame operation board module.