A second wind for wiring

Article Abstract:

Asymmetric digital subscriber line (ADSL) offers data transmission speeds as high as 6.144 Mbps from the Internet to homes (downstream) and 640 Kbps from a home PC to the Internet (upstream) using standard twisted-pair telephone wires. DSL provides a dedicated link to the local phone company's central office for each customer, whereas cable modems require that several users share a single coaxial cable. ADSL modems cost about $200, but slower ADSL Lite (also called Universal ADSL or G.Lite) devices will cost much less and can be installed by the customer, avoiding the cost of professional installation. Customers living more than 5.5 km from a central office cannot use ADSL service because attenuation is too high, but a terminal can be installed in the neighborhood and connected to the central office by optical-fiber cables and to subscribers by twisted-pair wires. Use of ADSL modems eases the workload of central office switches while simultaneously making it easier for customers to link to the Internet.

Digital Subscriber Line, DSL, DSL (Digital subscriber line), Design and construction, Technology overview, Digital Subscriber Line modems, DSL modems, DSL modem/multiplexer, DSL access multiplexers

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Data express: Gigabit junction with the next-generation Internet

Article Abstract:

In the Research Triangle in North Carolina a truly high-performance regional network is being developed. Partners from the academic, research and business communities, united in the North Carolina Network Initiative (NCNI), have set up a network ready to serve as a very high-speed point of presence (POP) called the GigaPOP, for handling multigigabit traffic for the next-generation Internet. The level of performance of POPs is as important as performance of the backbone is to the next generation of the Internet. At each node a Cisco router with dual 155-Mb/sec connections to the ATM switch is used. Primary nodes in the ring topology are at NC State, Duke Univ., UNC Chapel Hill, and MCNC, a not-for profit group that hosts the NC Supercomputer Center and the NC Research and Education Network. Local industry partners are IBM, Cisco, Nortel and Time-Warner Telecom, which provided a 4-fiber, 2 in, 2 out, ring infrastructure. Mapping ATM virtual circuits to Sonet circuits was challenge.

North Carolina, Computer networks, Telecommunications systems, Research Triangle Park, North Carolina

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Reduced time-to-market and higher quality

Article Abstract:

3M Telecom Systems Div., Austin TX, used solid freeform fabrication (SFF) to produce prototypes when it set up its FibrDome project in response to demand from the telecommunications industry. Short product development times were essential, and SFF was one way to achieve that. Telecommunications groups planned to upgrade networks to glass fiber instead of copper and needed a low-cost housing to protect fiber splices from weather and other hazards. For one situation, although stereolithography was mostly used, a stereolithography apparatus (SLA) polymer had too little strength and flexibility so laser sintering was used selectively for a structural polymer. The design turned out not to be feasible and much time and effort were saved. SFF prototypes are now standard for all 3M Telecomm Systems Div. projects. An oft-overlooked benefit from SFF is imporved communication between supplier and designer.

Other Communications Equipment Manufacturing, Fiber Optics Systems & Equip, Plastics Material and Resin Manufacturing, Engineering Services, All Other Miscellaneous Electrical Equipment and Component Manufacturing, Communications equipment, not elsewhere classified, Engineering Plastics, Plastics materials and resins, Product Development Engineering, Plastic Electrical Parts NEC, Product development, Electrical equipment and supplies industry, Electric equipment industry, Services, Fiber optic networks, Engineering firms, Prototypes, Engineering, Engineering prototypes, Product engineering, 3M Co. Telecom Systems Div., Plastic electrical parts

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