1
The highest level hub in a hierarchy of hubs. The header hub broadcasts signals transmitted to it by lower level hubs or DTEs, such that they can be received by all DTEs which may be connected to it, either directly or through intermediate hubs.; 套筒式设备分层结构中最高层的套筒式设备。套筒式设备将较低层套筒式设备或数据终端设备(DTE)发送给它的信号进行广播,因而与它相连的所有DTE都可以接收 这种信号,与它相连的所有DTE既可以直接相连,也可以经过中间套筒式设备相连。