【正文】 tor interfaces, a lack of standard transmission specifications, and the introduction of cabling schemes by vendors added to the user39。 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 today39。t 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, multitiered relational databases and other dataintensive 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 network 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 2010 or 2020? Microsoft39。s 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 twistedpair, 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 twistedpair (STP) systems are quite robust and provide greater signal headroom than UTP. However, they lag far behind UTP in customer acceptance for today39。s look at the proposed solutions for future requirements. Unshielded twistedpairCurrently, standards are being solidified to extend the transmission characterization of UTP to 250 MHz. Many manufacturers are advertising the availability of products that exceed yettoberatified specifications. Many technical hurdles have to be solved before a Category 6 standard is published. However, it is reasonable to expect that these hurdles both technical and political will be resolved. It is generally recognized that UTP has not yet been pushed to its theoretical limits. The question yet remains as to the continued viability of UTP as information speeds increase.If future technology does not improve the efficiency of bandwidth utilization, then the cost of the electronics, installation detail, and the testing requirements may diminish UTP39。s bandwidth limitations have not yet been reached, but as is the case with UTP, economics could be the major stumbling block to its adaptation. The installation of STP requires highly trained installers. North American industry experts doubt that end users or installation contractors will be quick to embrace STP. Fiberoptic WDM Wave division multiplexing (WDM) is a new technology that expands the datacarrying capacity of optical fiber rather than using a new media type for structured cabling systems. To increase the carrying capacity of fiber, the laser light that carries data through fiberoptic glass can be split into different colors, or more precisely, wavelen