Hi. I am sorry for the late reply. Actually I was waiting for some reply from our other friends. Its indeed an interesting topic and thanks for that. I think you should follow the G.O. No. 181-SE /5B-1/09, Dated, the 8th October, 2009.
I am quoting below the relevant para which will answer your queries.
(d) Untrained Secondary School Teachers shall be allowed annual increments in revised pay structure on condition that such untrained teachers will have to get themselves trained from any institute recognized by N.C.T.E. in regular or open and distant education mode within 5 years from the date of appointment. An untrained teacher of a recognized Secondary School with ten years teaching experience in recognized school shall be treated as a ‘trained’ teacher for the purpose of drawal of increments only (but not for applying to the post of Headmaster as a trained teacher) in the pay structure applicable to the teacher concerned after completion of one year from the date on which the condition of teaching experience is fulfilled.