The university students face 72 fraud charges, accused by Telecom of using computer generated dial tones to break into internal telephone exchanges to use vacant phone numbers to make free calls.
Investigators say the case is unprecedented in Australia.
It has forced Telecom to setup a national system of blocks to prevent computer hackers from breaking into telephone exchanges. The youths allegedly designed the software on a US system. It is alleged they then broke into the telephone exchange using a computer, a home telephone and a set of loud speakers. Investigators describe the accused youths as geniuses. But they are reluctant to talk about the case, fearing it could lead to copycat hacking.