The menace of pesky calls is likely to continue for another year at least as state-run BSNL has said that it will take 10 months after getting necessary approval to upgrade its network-- vital to implement TRAI's idea of identifiable number series to tele-marketing firms.

BSNL's upgrade of its network is essential as all calls are inter-connected irrespective of their origin and end.

The Telecom Regulatory Authority of India (TRAI) in its regulation to put a check on unsolicited calls and SMSes has directed telecom service providers to allocate easily identifiable number series for tele-marketing companies.

On a request from TRAI, the Department of Telecommunication has issued a number series starting with '140' to tele-marketing companies for mobile phone numbers but not for landline connections.

Adding three digit series to landline numbers will take total digits to 13. And to transmit a 13-digit number to telecom network, especially for caller line identification, BSNL and MTNL need to install modern equipment in exchanges.

"Private companies have said that they can upgrade their network in few weeks time but BSNL and MTNL will need time as government rule mandates them to procure equipment for upgrading network through tenders," DoT official said who did not wished to be named told PTI.

"BSNL has said that it will need at least 10 month time for this after government approval to meet all the requirement of TRAI's regulation," the official added.

BSNL has more than 38,000 telephone exchanges for landline connections throughout the country. According to the DoT official, almost all of these exchanges need to be upgraded to handle transmission of 13-digit number series.

BSNL officials denied to comment on the issue saying that new chairman and managing director of the company is likely to be appointed within a week and hence no one from company can comment on the issue.

Service providers have mentioned that mobile phone network alone cannot handle load of telephone calls that tele-marketers make and hence allocation of landline phone is must for running their business and prevent mobile network from congestion.

Telecom operators a in meeting held with DoT on April 13 have said that TRAI did not consult them on issues related identifiable landline number series before coming up with its regulation.

"Telecom operators have said they were not consulted on landline issue by TRAI. They have expressed their inability to provide only mobile resources for the operations of tele-marketing companies as they make large number of calls, which may choke their network," DoT official said.

Queries send to TRAI Chairman JS Sarma on this issue received no response.