A condition arising when two or more data stations attempt to transmit at the same time over a shared channel, or when two data stations attempt to transmit at the same time in two-way alternate communication.当两个或多个数据站想在同一时间通过共享信道发送数据，或两个数据站想在同一时间在双向交替通信中发送数据时产生的一种状态。
