... switch independence, support for the size of SIM card; 3,ports support hot-swapping; 4,a separate module can be demolished; ... very simple; 6,the size of a small, elegant, accounting for a smaller space (the volume is only the size of the computer keyboard) standard ... simple; 6,the size of a small, elegant, accounting for a smaller space (the volume is only the size of the computer keyboard) standard ...