New Delhi, Dec 16 : The Centre will come out with a list of "trusted" vendors and sources of telecom devices for in view of national security. The Cabinet Committee on Security on Wednesday approved the National Security Directive on telecom sector. Addressing the media post the cabinet meet, Communications Minister, Ravi Shankar Prasad said that the move is important for national security. He said that with an aim to maintain supply chain security, the Union government will declare trusted products for telecom. The methodology to designate trusted products will be devised by the designated authority, the National Cyber Security Coordinator, the minister said. Prasad further said that another list may also come up with designated sources from whom no procurement can be done. The existing telecom equipment with the services providers will not be impact by the move, he added. This year, amid border tensions with China, India has banned over 200 Chinese mobile apps and restricted certain investments from the norther neighbour. Further, the Union Cabinet on Wednesday also approved the next spectrum auction of a total of 2251.25 MHz. Prasad said that the auction will be held for spectrum in the 700 MHz, 800 MHz, 900 MHz, 1800 MHz, 2100 MHz, 2300 MHz and 2500 MHz frequency bands, for validity period of 20 years. A total of 2251.25 MHz will be offered with total valuation of over Rs 3.92 lakh crore /IANS