A.1級(jí)時(shí)鐘信號(hào) B.2級(jí)時(shí)鐘信號(hào) C.3級(jí)時(shí)鐘信號(hào) D.SDH設(shè)備時(shí)鐘信號(hào)
A.ADM B.TM C.REG D.DXC
A.155M B.622M C.2.5G D.10G