law: Telecom Regulatory Authority of India Act,1997
  13. Power of Authority to issue directions
  The Authority may, for the discharge of its functions under
  
  sub-section (1) of section 11, issue such directions from time to time to the
  
  service providers, as it may consider necessary:
   2  [PROVIDED that no direction under sub-section (4)
  
  of section 12 or under this section shall be issued except on the matters
  
  specified in clause (b) of sub-section (1) of section 11.]