本实施规程描述了在系统M（525/60）中运行、符合CCIR建议601-2附件1中定义的4:4:4编码参数、标称采样频率为13.5MHz的数字视频设备的互连方法。规定以10位精度传输信号，并携带第四个辅助通道，作为信号复用的一部分（产生4:4:4或4x4整体）。这种做法在电视演播室中的应用距离可达100米（320英尺）。

This practice describes the means of interconnecting digital video equipment operating in system M (525/60) and complying with the 4:4:4 encoding parameters as defined in CCIR Recommendation 601-2, annex 1 with a nominal sampling frequency of 13.5 MHz. Provision is made to convey signal at 10-bit precision and to carry a fourth, auxiliary, channel as part of the signal multiplex (yielding 4:4:4:4 or 4x4 overall). The practice has application in the television studio over distances up to 100 m (320 ft).