The Telecom Regulatory Authority of India has cracked down on cellular firms for blocking calls from wireless-in-local-loop services for some time in January after a dispute over sharing revenue.

The regulatory body has moved high courts in the circles where the calls were blocked and has sought permission to fine the implicated firms.

Officials said Trai had to take recourse to the law because the Trai Act did not empower it to punish. Trai has to seek permission before taking action against violators. The proposed fine on the cellular firms that blocked calls is a one-time payment of Rs 100,000and Rs 200,000 for every day they failed to implement the Trai order.

In January, cellular operators had refused to pass through calls from limited mobility operators, alleging that the revenue-sharing arrangement between the two was tilted in the latter's favour.

Following complaints from Tata Teleservices, whose calls were blocked, Trai had given cellular firms three days to restore connection. The cellular firms had, however, ignored the order.

Subsequently, Trai had given the cellular firms another 72 hours to explain their action and give reasons why punitive measures should not be taken against them. Meanwhile, Mahanagar Telephone Nigam Ltd had joined the fray and pulled the plug off cellular operators in Delhi.

Following negotiations with the communication ministry, the cellular firms finally decided to restore connection to WLL operators.

Trai officials said although the cellular operators had eventually complied with its orders, it had to punish them for their initial violation.

Trai was in the process of studying MTNL's explanation for disconnecting calls originating from cellular networks, the officials added.