多点控制单元(MCU)作为H . 323的一个主要部件，是进行多点会议的核心设备。

MCU (multipoint Control Unit), as one of H. 323 components, is the core equipment in multipoint conference.

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现场总线是安装在生产过程区域的现场设备、仪表与控制室内的自动控制装置、系统之间的一种串行、数字式、多点通信的数据总线。

The Fieldbus is located at the base layer of the production control and network frame and is directly connected with the factory field facilities;

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