e 7-33). These tanks - three in all, about 50 feet in diameter and 11 feet deep - hold 1,200 miles of cable, and weigh about 1,700 tons. The cable is fed into the tanks from the main deck, where it is coiled by hand- a process that takes days. Cable is pulled from the tanks as needed and fed down the stern deck of the ship through the cable supports visible in Figure 7-34. No question about it - this is one of the coolest tours I've ever had the honor to take. Another Brief Aside: Broadband over Power Lines (BPL) BPLs is the term created by the FCC to describe the new class of broad- band modems that can be used to deliver IP-based broadband services over electric power lines. In 2003 the FCC adopted a Notice of Inquiry (NOI) that expressed enthusiasm for the potential of BPL to allow elec- tric power lines to function as a third data connection to the home and to Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Transport Technologies Transport Technologies Figure 7-34 Arrows show the path of cable as it is pulled from the cable tanks. create competition for the naturally monopolistic copper telephone line and cable television coaxial cable line. BPL modems transmit signals over electric power lines in much the same way that cable and DSL modems transmit over cable and tele- phone lines. Recent advances in processing capability enable BPL devices to overcome challenges that are inherent in transmitting over the electric power lines. The FCC identifies two forms of BPL: in-house BPL, which uses trans- mission standards developed by the HomePlug Alliance, and Access BPL, a new technology to carry broadband Internet traffic over medium volt- age power lines. An inductive coupler connects the BPL modem to the power line. One key consideration is interference: There have been serious concerns expressed by the Amateur Radio Relay League (ARRL) about