Mumbai--Not happy with the decision of TRAI, Tata Teleservices has challenged in the Supreme Court, the TDSAT order that classified the company's fixed wireless phone service "Walky" as limited mobile.

With the TDSAT verdict, the private operator would have to pay a whopping about Rs 300 crore as levy to state-owned BSNL, as well as increase call tariff to Rs 2.10 for a three minute call from Rs 1.20 now.

When contacted, Tata Teleservices spokesperson confirmed from Mumbai that they have moved the apex court against the TDSAT order.

Last week, TDSAT had ruled that Walky service offered by Tatas was a mobile service, thus the private company was liable to pay a levy called Access Deficit Charge to state- owned BSNL as per the interconnect order of telecom regulator TRAI.

Tatas have been offering Walky services for more than a year now and they would end up paying close to Rs 300 crore to BSNL as the levy has to be paid retrospectively.

Tata Teleservices had also asked the Department of Telecom three months time to implement the TDSAT order, but did not get any respite.

According to sources, Tatas have also sought clarification with regard to existing subscribers that whether they would also be affected by the TDSAT order or whether only fresh subscribers would be covered by it.

Tatas had opposed paying the levy retrospectively, saying that subscribers prior to the TDSAT judgement should not be considered as WLL (M).

According to BSNL officials, as per the prevailing traffic pattern, it is expected that the total ADC due amount from Tata Teleservices and other service providers would be about Rs 450 crore from such services and and Tatas alone would have to pay about Rs 300 crore.