From The Hindu Archives, June 2, 1926: Reduced telephone rate

From The Hindu Archives, June 2, 1926: The Government of India in the Industries Department have sanctioned as experimental measure for one year with effect from 1st June 1926, that the telephone calls throughout India and Burma between hours of 8 p.m. and 8 a.m. will be charged at half the usual rates subject to the condition that the minimum charge for such a call at reduced rates will not be less than six annas.

Raccontata dathehindu.com