Rai will brief the JPC on Monday, May 30, chaired by Congress leader P C Chacko on the allocation and pricing of telecom licences and spectrum during 1998 to 2009.
The CAG, in a report to Parliament last year, had pegged presumptive loss to the exchequer on 2G spectrum allocation at Rs 1.76 lakh crore. The findings triggered a political storm and subsequent events led to the resignation of the then Telecom Minister A Raja.
"Today the talk is of a Rs 1.76 lakh scam. We want to know from the horse's mouth how he had arrived at the figure," Chacko said after the last meeting of the committee on May 18.
Telecom Minister Kapil Sibal had dubbed "utterly erroneous and without any basis" the estimated loss of Rs.1.76 lakh crore, arrived at by the CAG on account of 2G spectrum allocation.
According to the CBI charge sheet in the 2G spectrum allocation case, the loss to the exchequer is pegged at Rs 30,984 crore.
The JPC has decided to call CBI Director A P Singh to brief on the 2G case at its meeting on June 7, while the Finance Secretary, chief of Enforcement Directorate, and Telecom Regulatory Authority Chairman J S Sarma will make presentations on the issue.
Sarma had begun his presentation on the functioning of TRAI and its role in the telecom sector which was inconclusive and would continue on June 8.