Avaya must give its customers access to maintenance software for some enterprise phone switches so they can service the systems themselves or hire a third party to work on them, a federal judge has ruled.

The June 30 ruling by Judge Joseph Irenas of the U.S. District Court in New Jersey follows a years-long court battle in which a jury decided in March that Avaya had illegally tried to block competitors from servicing its enterprise phone systems. Continuant, a third-party support company based in Washington state, won a US$20 million damages award that is expected to be tripled. The company sought the injunction following that verdict.

The case is just the latest dispute over who can perform maintenance and repairs on hardware systems that are increasingly defined by software. These fights extend beyond the IT industry to cars and other products. It’s not the first time independent third parties have won the right to continue performing service, and the outcome of this case is not expected to take maintenance law in a new direction.

The June 30 ruling affects Avaya-branded PBX (private-branch-exchange) systems purchased between Jan. 1, 1990, and April 30, 2008. Avaya has six months to comply. The maker of enterprise networking and communications technology has to let owners access the On Demand Maintenance Commands on those systems. With access to those commands, owners will be able to either maintain their own PBXes or hire independent support providers such as Continuant to provide service.

Avaya plans to appeal the case to a higher court. “The Company continues to believe that TLI/Continuant’s claims are without merit and unsupported by the facts and law,” the company said in a statement.