The serial port on the 8051 has been enhanced on the 83C51FA with the addition of two new features: Automatic Address Recognition and Framing Error Detection. Automatic Address Recognition facilitates multiprocessor communications by reducing CPU overhead. Framing Error Detection increases communication reliability by checking each reception for a valid stop bit. This Application Note explains how to use these new features with samples of code for typical applications. A section is also included which reviews how to set up the serial port for multiprocessor applications.