covert@COVERT.DEC.COM.UUCP (07/18/86)
From the Wall Street Journal, 26-June-86, included without permission. Survey: Sharks Prefer AT&T Lines By Wide Margin Over Sprint, MCI ------ ------ ------ ---- ----- -- ---- ------ ---- ------- --- By Bob Davis Staff Reporter of The Wall Street Journal Just when American Telephone & Telegraph Co. thought it was safe to go into the water, sharks began dining on its newest undersea telephone-communications cable. It seems the sharks just can't get enough of AT&T experimental underwater fiber-optic telephone cable near the Canary Islands. They munch on its plastic covering, gnaw on its electrical innards and eventually short-circuit it-even though they may electrocute themselves in the process. At least, "we came up with some pretty effective shark bait," says an AT&T spokeswoman. At first, AT&T engineers didn't know what was causing the cable failures. Then they raised the cable and found rows of shark teeth sticking out of it. "Sharks will always be attracted to magnetic fields," which the fiber-optic cables create, says James Barrett, an AT&T engineering official. Transatlantic Race That's the big problem because AT&T is hurrying to complete the world's first transatlantic fiber-optic cable by 1988. The cable uses glass fibers instead of copper wires to transmit conversation and data. AT&T's old cables generally are shark- free because they don't emit much magnetism. But a shark bite helped knock out the Canary Island fiber-optic cable for a full week. AT&T says it can combat the sharks by reinforcing stretches of the cable with steel wire and quickly patching breaks that occur. But the company's shark problem has attracted another kind of predator. Space Shark Communications Satellite Corp. (Comsat) a Washington, D.C., satellite company, is pressing Congress to spend $119 million next fiscal year on a new satellite system that will compete with fiber optics. Meanwhile, Comsat officials are turning AT&T fish difficulty to their own advantage: Shark attacks "may cause a delay of six months to a year," in laying AT&T's transatlantic cable, asserts John Evans, a Comsat vice president. AT&T denies any such delay. And even Comsat's lobbyist, Thomas Scully, doubts that Congress will swallow the fish story. He reasons: "If I were at AT&T and I saw an article saying the biggest problem facing fiber optics is that fish eat the cable, I'd say, "Boy, the satellite people are desperate." -30- Notes: The person from whom I originally received this article was immediately sceptical of the reports of magnetic fields from fiber optic cables. But unlike short-haul terrestrial fiber cables, where the fiber would not emit any fields, undersea cables must carry high voltage power to the undersea repeaters, which would result in both electric and magnetic fields around and along the cable. The article is further misleading in stating that old cables are shark-free because they don't emit much magnetism. It appears that the real reason here is more likely to be because the conventional cables are a larger diameter which the sharks can't so easily get their teeth around. And finally, experiments have shown that sharks are attracted to electrical fields which many of their prey emit. There is little to no data about magnetic fields and shark. I have, however, read articles about other animals using magnetic fields for navigation. /john