All Solved!!!

I know that the issue was on Clock, or better, in wrong clock serial syncronization.
So I have change the Internal Oscillator with a External quarze and made the code
changing to use it. Now all work very good and without any problem.
I have take a look on 16f676 Datasheet where is writted than internal clock have a
little tollerance about on some kilohert. But in other forum discussion I have found
than the internal clock is barely enought in use on serial asyncronous comunications.
This is my case.
Maybe if I work on OSCCAL calibration I will use the Internal clock.
But if I put OSSCAL issue on Picbasic source the PBP give a error, like if OSSCAL is
not avaible on 16f676.
I have lost a week on this problem but now all is over and in anyway I have get more
experience about use and expecially the "non-use" of internal oscillator for some specified
task like comunications, where is very important have a good timing.
Thank to all friends to have spend their time on this post and for goods solution proposed
to me.
This forum is a very good mine of competent and friendly people. I will hope to give some
contribution in future.
Thanks again.