L2/L3 Switch#:it implements the frame or packet switching according to six-byte MAC address or IP 4-byte address. r7r Digital eXchange Cross connect DXC,数字 交叉连接)#：it performs time slot-,! port-, wavelength-switch by configuring manually. Multiplexor (复用器)#：it can multiplex several low channels (say 64Kbps)into one high speed channel (say E1),and vice versa. ETUO2-MUX/PLUS E1数据、语音复用器 Concentrator (集中器)#：it usually collects information from quite a number of users, and transfers the information captured to a 据吴生器子阳 high-level server,e.g., remote electricity /=旦土右小台 L2/L3 Switch#: it implements the frame or packet switching according to six-byte MAC address or IP 4-byte address.  Multiplexor ( 复 用 器 )#: it can multiplex several low channels (say 64Kbps) into one high speed channel (say E1) , and vice versa.  Digital eXchange Cross connect (DXC,数字 交叉连接)#: it performs time slot-, port-, wavelength-switch by configuring manually.  Concentrator (集中器)#: it usually collects information from quite a number of users, and transfers the information captured to a high-level server, e.g., remote electricity meters reading (远程电力抄表)