Warsaw Pact and TI

[DRG]

I'm tossing this out in the hopes that some of you will have solid information. I'm not really interested in opinion ( nationalistic or otherwise.......) or anyone who starts the answer with ...."I think" unless it's " I think my uncle said he trained on one at his base in Poland/Hungary/Czechoslovakia/Russia etc etc in either 1986 or 1987".....that type of thing.

I'm really only interested in hearing from someone who KNOWSand can back it up with a varifiable source

What year did the nation members of the "Warsaw Pact" start using TI ( what we enter into the OOB's as "40" for vision ) If Anyone has info on China that would be welcome as well

Thanks

Don