I doubt very much that "man stty" will lead anywhere useful.

In a few environments it is possible to exchange the roles of the escape and tab keys completely. I could do it on my X terminal with the keymap editor. And I see that sun has a "pcmapkeys".

But I doubt that the OP really wants to do that.

I think that RTM is on the right track. Most likely the OP has switched from one program to another and the two programs are using different keys for some function.