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Fiber Optics Illustrated Dictionary - Part 9

The Fiber Optics Illustrated Dictionary - Part 9 fills a gap in the literature by providing instructors, hobbyists, and top-level engineers with an accessible, current reference. From the author of the best-selling Telecommunications Illustrated Dictionary, this comprehensive reference includes fundamental physics, basic technical information for fiber splicing, installation, maintenance, and repair, and follow-up information for communications and other professionals using fiber optic components. Well-balanced, well-researched, and extensively cross-referenced, it also includes hundreds of photographs, charts, and diagrams that clarify the more complex ideas and put simpler ideas into their applications context | Fiber Optics Illustrated Dictionary that supports mid-range speeds and the transmission of both voice and data over existing copper-pair wires. ADSL is becoming a popular cost-effective option for faster computer network access e.g. Internet in households and small businesses. It enables users to be online virtually all the time without interfering with the use of the phone for voice messages or having to dial the service provider each lime access is desired. ADSL services are competitive with cable modem. Asymmetric refers to the discrepancy between the upstream and downstream transmission speeds. Most users download far more than they upload so a compromise is established to balance cost and speed. Thus download speeds are configured to be faster than upload speeds e.g. 640 kbps versus 8 Mbps . Installation of ADSL service involves installing a network interface device NID that houses a splitter a low-pass filter at the subscriber premises. Separate lines run from the splitter to the phone and from the splitter to the ADSL remote transceiver somewhat like a traditional modem which in turn connects to the computer. Software to handle communications is installed on the computer. The combined telephone and ADSL signals travel from the loop to the subscriber NID where the signal is split. The telephone signal is then directed to the phone set and the ADSL signal is directed to the terminal unit the remote transceiver where it is processed and transmitted to a network interface card NIC installed in the computer. Much the same happens in the reverse direction. Phone and ADSL signals coming from the subscriber premises are sent to the central office where a splitter sends phone signals to the voice switching mechanisms and ADSL signals to the data network where an Internet Services Provider handles user requests such as Internet access Web hosting etc. Copper wire lines are not optimal for ADSL as bridge taps and load coils on utility poles can interfere with ADSL .