Mac cloner Psystar has asked the court hearing its copyright tussle with Apple to let stand charges that Apple's technology and marketing tactics breach federal antitrust laws.

Psystar filed the charges in a counterclaim in August in response to an Apple lawsuit that accuses Psystar of copyright violation. Apple asked the court to dismiss the counterclaim earlier this month.

But in a motion filed with U.S. District Court for Northern California last week, Psystar said its claims against Apple should stand. Apple's contention that Psystar is "trying to 'force' and 'require Apple to help its competitors compete against it'" is false, Psystar said in court papers. That argument, said Psystar, "is a fundamental subversion of the real issues."

Psystar's countersuit claims that Apple's dominance of the market for its own products violates Sherman antitrust rules and other U.S. laws. A Psystar victory could pave the way for other PC makers, including big vendors like Dell, Hewlett-Packard, and Lenovo, to enter the Mac market and offer alternatives to Microsoft Windows PCs.

Apple's motion to dismiss Psystar's counterclaim says the counterclaim is based on the false notion that Macs represent a market that is separate and apart from the rest of the PC industry, and that Apple uses unfair tactics to dominate that market.

Apple filed its original copyright suit against Psystar in July. Psystar sells low-cost knockoffs of Apple's pricey Macs -- including models that run the new OS X 10.5 "Leopard" operating system -- from a nondescript warehouse in Miami. Apple claimed that the clones violate its copyrights over the Mac OS and asked the court to order Psystar to discontinue sales.

For its defense and countersuit, Psystar has retained high-profile Silicon Valley law firm Carr & Ferrell. A trial date for the case has not been set. Last week, a judge placed the case in the court's dispute resolution program, but it will likely proceed to trial if a settlement isn't reached.