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1、 毕业设计外文文献及译文文献、资料题目:The future of structure cabling systems文献、资料来源: Cabling Installation & Maintenance Magazine 文献、资料发表（出版）日期: 2005.12.1 院（部）: 信息与电气工程学院 专 业: 电子信息工程 班 级: 姓 名: 学 号: 指导教师: 翻译日期: 2012.4.1 外文文献： The future of structured cabling systemsWhich technologies will meet speed and data-transmiss
2、ion requirements in the future?To discuss the future of structured cabling systems, we should spend a moment looking at the past and present practices. Before early 1984, communications wiring systems, as they were then called, were not topics of much discussion. Data-transport speeds were comparati
3、vely slow, transmission bandwidth requirements were minimal, and others provided the design and installation of the cabling system. The telephone companies took care of the installation and maintenance of the telephone service. When data services became distributed, the cabling system was vendor-spe
4、cific, and the installation and maintenance of the cable plant was provided by the equipment vendors, or specialized independent contractors.In January 1984, the courts in the U.S. made several important rulings that changed the way telecommunications was provided and distributed. Outside of traditi
5、onal suppliers of cabling systems, not much was understood about the cabling requirements for communications transport. The proliferation of media and connector interfaces, a lack of standard transmission specifications, and the introduction of cabling schemes by vendors added to the users confusion
6、. Bringing order to the confusion and creating generic cabling systems demanded the creation of a standards body whose output would focus on commercial buildings and communications cabling.Since the introduction of the first cabling standard in1991 by the Telecommunications Industry Association/Elec
7、tronic Industry Alliance (TIA/EIA), that same group has issued a series of standards and specifications regarding most aspects of the structured cabling systems. These standards have provided guidance related to evolving high-speed information transport systems. The vast majority of past and present
8、 digital communications, used in the commercial world, has been transported on unshielded twisted-pair (UTP) cabling systems. UTP became the medium of choice because it was economical, perfectly adequate for the applications, and comparatively easy to install versus other available media types.With
9、advancements in network speeds, new transmission specifications for UTP cable and connecting hardware have been promoted by manufacturers and eventually endorsed by the standards community. In 1991, the highest rated bandwidth over UTP was 16 MHz; we are now faced with transport speeds demanding tra
10、nsmission bandwidths of 250MHz and beyond. Manufacturers have risen to the challenge and provided UTP components for todays transmission requirements in excess of 600 MHz. What media and connectors will be available that will be economically feasible at bandwidths of 1G MHz? At what point does UTP b
11、ecome less easy to use and less economical than other media?Future directionsAs far as we can see into the future, commercial information transfer will consist of both low-speed and high-speed requirements. Applications such as voice, building automation systems, alarms, and security systems will st
12、ill use low bandwidths. Voice information may change from central office exchange delivery to intelligent peripheral, but bandwidth requirements wont increase by a large amount. The data packets, with which the voice packets ride, will increase bandwidth requirements. The requirements to transport l
13、arge amounts of information in shorter and shorter periods of time are changing, and will continue to change. Applications such as graphical data (both schematic and pictorial), scientific modeling, desktop videoconferencing, multi-tiered relational databases and other data-intensive information wil
14、l drive up the bandwidth requirements.If history is any predictor of the future, we will see information transfer speeds increase at least one order of magnitude per decade. We have seen local area network speeds, on UTP, increase from 10 Mb/s in the mid 1980s to 100 Mb/s in the mid 1990s then to 1
15、Gb/s in the late 1990s. Today, standards are being written for 10 Gb/s. Where will we be in 2010 or 2020? Microsofts Bill Gates is quoted as saying, We will have infinite bandwidth in a decades time. Lawrence Berkeley Laboratory (Berkeley, CA) has projected its throughput needs for 2020 to be 40 Gb/s. What will be its media of choice: UTP, coaxial, shielded twisted-pair, optical fiber, or wireless technology?The two major properties required for any cabling system to be the system of choice a
