schematic for RS 232 to RS 485 converter

I understand it now. But that should not happen.. check if packet format is same? and also check if number of bytes you're sending are fine in both cases.

Yes I have checked them often but i m not getting perfect data...

you are using MODSCAN on PC? did you try using some terminal software to check if data received is correct or not?

Ok i will check and tell what happen.