It just kept on triggering the INT and after many changes (which led to a spaggeti program) I gave up.

I just used the good ol' array transmit like this: Hserout [str array\n].

When I feel like in a good mood I may try it again and see how it goes.

As for the Rx Buffer, you ideas are good.

I once tried the index pointer with a long array and no end of fle check. If characters kept coming then just over writen the previous characters in the array.

Ioannis