Taking cognizance of cellular operators' complaint, Telecom Regulatory of India has asked Reliance Infocomm to explain about roaming services being promised by them on their WLL phones.

"Offering WLL services outside local call area known as Short Distance Charging Area is prohibited and we have asked them (Reliance Infocomm) to explain their position," TRAI counsel said in the Telecom Dispute Settlement Tribunal.

TDSAT, however, declined to pass any direction with regard to Reliance's advertisement, which has been promising value added services like roaming on their WLL phones.

The case would come up for hearing on February 17.

Informing the tribunal about Tata Teleservices' alleged WLL coverage outside SDCA, TRAI counsel Meet Malhotra said they (Tatas) have given a "categorical assurance" to the regulator that their WLL services would not be available outside SDCA.