NEW DELHI/MUMBAI: Looks like conditional access system (Cas) will spread to fully cover the metros of Delhi, Mumbai and Kolkata.

"The introduction of Cas in some parts of the metros has proved successful and it would be extended to other areas in these cities soon," the information and broadcasting minister Priya Ranjan Das Munshi said today at a press conference in Delhi.

The set-top boxes (STBs) seeded in these three cities, according to the Telecom Regulatory Authority of India (Trai) chairman Nripendra Misra, has already touched 382,000.

Of the 1.2 million subscribers in the Cas areas, Trai's estimate is that digital conversion would be at 50 per cent by February-end. "The indication that we are getting is that there would be 600,000 digital subscribers including direct-to-home (DTH) in the Cas notified areas of Delhi, Mumbai and Kolkata," said Misra.

In a meeting with the broadcasters today, Trai said it was aware that in some areas there was relay of pay channels without encryption. The regulator assured that the enforcement machinery would be energised to sort out such related issues.