Telecom Regulatory Authority Of India - Subsection
Section 1(3)(a) in The Telecom Consumers Protection and Redressal of Grievances Regulations, 2007
(a)all service providers including Bharat Sanchar Nigam Limited and Mahanagar Telephone Nigam Limited, being the companies registered under the Companies Act, 1956 (1 of 1956) providing, -(i)Basic Telephone Service;(ii)Unified Access Services;(iii)Cellular Mobile Telephone Service;