WASHINGTON (AP)-Telephone companies are declaring war on thousands of college students,professionals, and even prisoners who get into the telephone network illegally and ring up a half billon dollars in unpaid calls a year. Companies are changing the software as well as the hardware in their netwoeks to try to block calls, and they are offering amnesty programs on college campuses for students to fess up and pay up. They also are working with federal authorities to prosecute call-sell operators who are using stolen authorization codes and electronic devices to break into the network and sell calls to all parts of the world at drastically dicounted prices. "We look at it as a major problem, and it's definately well worth going after this half billion dollars," said Rami Abuhamdeh, executive director of the industry-sponsored Communucations Fraud Control Association. (CFCA) "In any industry, if you don't do anything about it, it's only going to fet worse." Computer-literate college stuents are among the biggest offenders and their campuses are breeding grounds for large-scale theft. Authorization codes get passed around quickly, allowing students to phone home for free, telephone company security officials say. "That's something we're going to have to deal with because college students have inquisitive minds and they like to do things like challenge the network," said Neal Norman, security manager for AT&T. MCI officials say they recently pursuaded 1,000 students at North Texas State University in Denton, Texas, to turn themselves in and pay about $100,000 for the illegal calls they made. At American University in Washington, D.C., 400 students turned themselves in and are being billed for about $25,000 so far, MCI spokesman John Houser said. Computer hackers -- including doctors, lawyers, and some housewives -- who search computer files for authorization codes are another problem. Abuhamdeh says their heaviest damage is in selling the codes or posting them on BBSs. The Hackers themselves usually don't make as many calls as ither groups, including prisoners, he said. "Prisoners have a lot of time on their hands and they're very innovative. And unfortunately in a lot of places, they have access to phones continually," AT&T's Norman said. In on case, Norman said, a prisoner called a hospital, identified himself as a doctor and asked to be connect to another number in the hospital. When that number answered, he asked to be switched to the hospital operator, whom he asked to connect him to an outside line to for a long-distance call. Companies are using sophisticated computer technology to identify patterns of illegal calling, which are often traced to operations run by "call selllers." "They make $2,000 a week selling calls, and that's tax free," said Martin Preede, a special agent for corporate security at NY Telephone Co. But He warned that phone companies are actively tracking down such operations and prosecuting. Typed in from a local newspaper. Article was written in late April. Courtesy of The Wiz Kid.