在用语音服务、非侵入式测量设备（INMD）测量网络中四个接线点的活动语音电平、噪声电平、语音回波路径损耗和语音回波路径延迟。因此，如果可以确定这些参数的性能和维护限制，它可以用于识别网络异常。由于性能目标因网络供应商而异，因此不存在唯一的传输限制。本报告提供了一种基于网络供应商特定目标确定INMD性能和维护限制的方法。由于这种方法是通用的，它还可以用于未来的INMD，用于测量其他服务参数，如模拟或数字数据、ISDN、数据包等性能参数。

The voice services In-Service, Non Intrusive Measurement Device (INMD) measures active speech level, noise level, speech echo path loss and speech echo path delay at four wire points in the network. As such, it can be used to recognize network anomalies if performance and maintenance limits on these parameters can be established. It is recognized that unique transmission limits do not exist since the performance objectives vary with network providers. This report provides a methodology for establishing INMD performance and maintenance limits based on the network provider's particular objectives. Because this methodology is generic, it can also be used for future INMD that measure other service parameters such as analog or digital data, ISDN, packet, etc. performance parameters.