In this paper the communication and collecting data and the design of software and hardware are elaborated . in the construction of network , this system adopt both direction circle redundancy network . making use of its advantage can transfer data by both direction , so without reference to anyone node has error that can not affect natural working 在网络拓扑结构上本系统采用双向环形冗余网络(双环形以太网) ，利用双向环形冗余网的特点可以双向传输数据，因此不论任何一个节点出现问题都不会影响正常的工作状态，假设在某一方向出现了问题可以通过另一方向传输数据，这样就更增加系统的实时性、稳定性。
We study the cost of metro wdm in two aspects in chapter 2 . for the aspect of components , a bidirectional optical add - drop multiplexer ( boadm ) using fiber gratings and circulators is designed , and is cheaper , simple and appropriate compenent for single - fiber bidirectional ring networks ( sfbrn ) . for the aspect of network , after study the traffic - grooming problem and the cost of wdm ring networks , a layered network with a multi - hubs is presented to reduce the total number of the network ports 在第三章，我们搭建了一个可以实现多业务单纤双向传送的sdh wdm网络平台，以单根50km光纤作为物理媒质，以mux demux的为单纤双向复用器件，以sdh wdm为传输手段，采用mstp技术，通过接入vlan模块建成一个单纤双向传输的局域网，并以此为基础通过接入图像编解码器实现单纤双向视频传输，为城域宽带接入网的多业务实现提供了范例。
Making use of the powerful capabilities of the pci chip , high - speed data of the dsp platform are transferred both ways at dma mode , and low speed data such as initialization and configuration information are transferred at direct slave mode . this paper shows in detail the workings of pci9054 , the configuration of its control register , and the writing of platform driver with api functions provided by the manufacturer 利用pci接口芯片的强大功能，本文提出了采用dma模式双向传输dsp平台的高速数据，采用从模式传输初始化信息及配置信息等低速数据，并详细介绍了pci9054的工作方式，控制寄存器的配置以及调用厂商提供的api函数编写平台驱动程序。
According to the demand of emergency monitoring , the selected and prepared equipments should have fast response to pollutants , gain of the accurate monitoring data , analysis , judgement forecast of pollution tendency , two - way transmission of audio - visual information , as well as safety control and protection function 分析了应急监测装备的配置形势,提出了应急监测装备的配置思想和配置原则,剖析了配置的关键点在于实现快速响应功能,准确、快速监测数据获取功能,快速解析、准确判断污染趋势功能,图像和声讯实时双向传输功能,以及安全保障和防护功能。
