电子信息工程外文翻译w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Cabling Installation ; MaintenanceMagazine文献、资料发表（出版）日期: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:w外文文献：The future of structured cabling systems Which technologies will meet speed and data-transmission 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, munications wiring systems, as they were then called, were not topics of much discussion.Data-transport speeds were paratively slow, transmission bandwidth requirements were minimal, and ;others; provided the design and installation of the cabling system.The telephone panies took care of the installation and maintenance of the telephone service.When data services became distributed, the cabling system was vendor-specific, 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 telemunications was provided and distributed.Outside of traditional suppliers of cabling systems, not much was understood about the cabling requirements for munications 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.Bringing order to the confusion and creating generic cabling systems demanded the creation of a standards body whose output would focus on mercial buildings and munications cabling.Since the introduction of the first cabling standard in1991 by the Telemunications Industry Association/Electronic 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 digital munications, used in the mercial 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 paratively easy to install versus other available media types.With advancements in work speeds, new transmission specifications for UTP cable wand connecting hardware have been promoted by manufacturers and eventually endorsed by the standards munity.In 1991, the highest rated bandwidth over UTP was 16 MHz; we are now faced with transport speeds demanding transmission bandwidths of 250MHz and beyond.Manufacturers have risen to the challenge and provided UTP ponents for todays transmission requirements in e_cess 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 bee less easy to use and less economical than other media? Future directions As far as we can see into the future, mercial information transfer will consist of both low-speed and high-speed requirements.Applications such as voice, building automation systems, alarms, and security systems will still use low bandwidths.Voice information may change from central office e_change 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 large 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 will 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 work speeds, on UTP, increase from 10 Mb/s in the mid 1980s to 100 Mb/s in the mid 1990s then to 1 Gb/s in the late 1990s.Today, standards are being written for 10 Gb/s.Where will we be in 2021 or 2021? Microsofts Bill Gates is ed as saying, ;We will have infinite bandwidth in a decades time.; Lawrence Berkeley Laboratory (Berkeley, CA) has projected its throughput needs for 2021 to be 40 Gb/s.What will be its media of choice: UTP, coa_ial, shielded twisted-pair, optical fiber, or wireless technology? The two major properties required for any cabling system to be the system of choice are its performance and its relative economics (which include ease of installation).Undoubtedly, fiber and shielded twisted-pair (STP) systems are quite robust and provide greater signal wheadroom than UTP.However, they lag far behind UTP in customer acceptance for todays applications.But will UTP and other media systems provide t