SAN FRANCISCO (AFP) – A federal judge has cleared the way for Apple's ailing leader Steve Jobs to be deposed in a class-action lawsuit charging the iPod maker turned iTunes into a digital music monopoly.

US Magistrate Judge Howard Lloyd ruled on Monday that attorneys for the plaintiffs may question Jobs for a total of two hours, but only about an iPod update making RealNetworks digital music inoperable with iPod MP3 players.

Lloyd determined that Jobs "has unique non-repetitive, firsthand knowledge" relevant to the six-year-old case, according to court documents.

The suit charges Apple with creating a monopoly by shackling digital music with FairPlay anti-piracy software that prevented iPods from playing song downloads from anywhere but the firm's online iTunes shop.

RealNetworks in 2004 released Harmony software crafted to let its music be played on iPods, but Apple quickly released an update that shut out the Seattle-based company's digital files.

With Jobs leading the charge, Apple did away with digital rights management software on iTunes music in 2009.

Jobs, 56, went on medical leave in January for an unspecified illness, but remains involved in running the California company and hosted the unveiling of second-generation iPad tablet computers in San Francisco early this month.

It was not indicated when the deposition might take place.