在通信链路上出现的噪音或无用的信号，它损害语音、数据的接收或正确的解释。
On a communications link, noise or unwanted signals that impair the receipt or correct interpretation of speech or data.
在网络中，指由数据链路连接的或共享公共控制的设备、程序或区域。
In a network, pertaining to devices, programs, or domains that are connected by a data link or that share common control.
一种传送控制字符，用于指明一个或多个后继的位模式不能正确地解释为系统编码或系统链路协议中的字符。
A transmission control character used to indicate that one or more of the following bit patterns have no correct interpretations as characters in the code or link protocol of the system.
