MEXICO CITY — Carlos Slim’s telco Telmex has won a key legal battle, expediting an answer to the billionaire’s request for entry into Mexico’s feevee promised land.

The company announced late Wednesday that a judicial ruling has given Mexican regs 15 days to say yea or nay to letting Telmex offer audio and video to subscribers.

Kicking into high gear in February, Mexico’s three, most powerful media moguls — Slim, Emilio Azcarraga Jean of Televisa, and Ricardo Salinas Pliego of TV Azteca — have been fighting for entry into each others markets, as each seeks to capitalize on new triple- and four-play schemes, bundling pay TV, Internet, fixed-line and mobile telephone services, while doggedly trying to hold onto their own empire.

Starting in 2006, Telmex has seen its attempts to gain a TV broadcast license denied repeatedly, while Televisa won clearance in 2007 to run triple-play plans via its cablers.

In May 2009, Televisa and other cablers launched the low-cost triple-play plan Yoo that has been steadily bleeding customers from Telmex, dealing a blow to the telco’s bottom line.

Telmex has repeatedly complained that regulators have been sitting on their hands while competitors lock down the market. Telmex insists it has complied to every reg demand handed to them.

Short of winning full, terrestrial broadcaster status, feevee approval would be a huge win for Telmex and a personal victory for Slim.