Even as the Group of Ministers on telecom is considering ways to limit the mobility of wireless in local loop services, Tata Teleservices has quietly begun to offer multiple registration.

This service enables its WLL subscribers to use the same mobile handset, while roaming between different short distance charging areas.

Reliance Infocomm already offers this service to its subscribers.

As per the subscription invoice issued on Wednesday to five different subscribers, Tata Teleservices was providing at least two different phone numbers to its WLL limited mobility subscribers in Maharashtra, which allows them to roam between Mumbai, Navi Mumbai and Kalyan with the same handset.

As per the licence conditions of WLL limited mobility services, the operators are not supposed to offer roaming services. However, WLL operators, like Reliance Infocomm, have found a way to beat the rule with services like call-forwarding, which allows subscribers to move from one SDCA to another.

Tata officials claim they are not offering the same service as that being offered by Reliance Infocomm. A Tata statement said, "Tata Teleservices Maharashtra wishes to clarify that it does offer multiple registration without call-forwarding facilities, only to its subscribers in Mumbai and adjoining SDCAs of Kalyan and Navi Mumbai. This enables a TTML subscriber to register in any two out of three SDCAs in this region, with a different number for each SDCA that he registers himself."

This means that a caller dialling a Kalyan-based Tata Indicom subscriber in Navi Mumbai will not only have to dial the subscriber's Navi Mumbai number but also pay STD charges.

In Reliance's case, they pointed out, the switching between numbers happens automatically without the knowledge of either the caller or the subscriber. In Reliance's case, subscribers are registered in multiple SDCAs and are given a phone number for each of the SDCAs that they travel.

As they move, the operator's network keeps routing the call to the number of that particular SDCA.

While Reliance has maintained that call forwarding was part of the basic services licences and the service was different from the roaming facility offered by cellular operators, the issue is being discussed by the Group of Ministers on telecom.