In line with the national numbering plan for mobiles as mandated by the Telecom Regulatory Authority of India for universal access licences, Tata Indicom will shift to the 10-digit numbering plan with effect from Thursday midnight in the Maharashtra circle and across the country "within the next few days."

The number-change, which would be implemented in the Maharashtra circle from Thursday midnight, would be applicable to all its mobile customers across the country within the next few days, Tata Teleservices (Maharashtra) Ltd said in a release.

TTSL has been assigned the "92" series by the Department of Telecom. Once this change is in effect, the numbering plan of Tata Indicom mobiles would be similar to other GSM mobile operators, it said.

Since Mumbai and the rest of Maharashtra are defined as different circles by Trai, calls between Tata Indicom customers across these two circles would be considered as STD calls, it said.

Apart from informing its customers, TTSL would also allow calls and SMS to be received on both old and new numbers till June 30.

TTSL chief operating officer (Maharashtra circle) Y V L Pandit said the Tata Group company would be the first licence provider to announce the 10-digit numbering plan in line with the Trai regulation and all measures were being taken to migrate to the new system without any hassles.