Erik Said:
Suresh, I do not know how much your time is worth, but I am sure the two months you have spent fooling around with this board cost more than a new documented board would have cost.

Erik, This is not the only work iam carrying on for the past few days. To mention, i did a simple design and a PCB for cropping machine control.
To be frank, being only person in the department, iam always asked to do works that the management wishes to do first(even if the prior is not completed). Iam just holding an year of experience and still need more things to learn which i find it difficult when working alone. Here my nature of work would be from getting the spec's from an existing model(if exists, else new)... to replacing it with a new design.
But i believe this type of experience would help me learn things at a broad spectrum.

Erik Said:
Believing you "have" something for which you do not have instructions/datasheed/description/.. is fools errand.

I have datasheets, and a manual written by the person who designed it. But the manual is not that descriptive that i could get all necessary information from it.

Jez,
I didnt ignore your idea. but couldnt get a clear view on the selection of an RC tme constant. Secondly, i found that Erik's suggestion with that bounce measurement issue is quite simple.
just look for bounce-start timer-then, for succeding transitions latch the Timer value and read it. it seems to be simple to try out first.

Suresh.