Before the autonegotiation protocol was widely used, people would sometimes manually configure one system to use fullduplex, but the other would use half duplex.
The UTP Ethernet variants support an additional autoconfiguration protocol that allows two Ethernet systems to negotiate which speed to use, in full or half duplex mode.
这种衍生的UTP电缆支持一种“自动配置协议”，允许两个以太网系统自行决定采用全双工抑或半双工操作。
3
Unlike HDR, the communication occurs using a fullduplexprotocol.