Dear my all friends, I am a new user of RS485 serial communication but I do not know how to trans and receive multiple bytes without any data loss as well as errors or jitter. My MCUs are 89C51 family (89S51,DS89C420..), in fact, my trouble is how to control a communication session with multiple-byte data frame using serial port of 89C51 family. I should use interrupt routines or main loop to process that session ??? Any one help me, please..., thanks!