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信息和信息高速公路 1、信息和信息网络 信息主要表现为三种形式(即媒体):图像、声音和文本(数据)。目前,图像主要通过电视网传输和提供,为单向服务;声音主要通过电话网传输和提供,为双向对称服务;文本主要通过数据网(计算机网)传输和提供,为双向对称或非对称服务。表1列出了各种信息网络的特点。可以看出,信息网络的发展方向是数字化、综合化、智能化、宽带化和个人化。
Information and Information Highway 1, information and information Network information mainly in three forms (ie, media): image, sound and text (data). At present, the images are mainly transmitted and provided through a television network, and are unidirectional services. Voice is mainly transmitted and provided through the telephone network, and is a bidirectional symmetrical service. Texts are mainly transmitted and provided through a data network (computer network), and are bidirectional symmetric or asymmetric services . Table 1 lists the characteristics of various information networks. It can be seen that the development of information networks is digital, integrated, intelligent, broadband and personal.