The Texas Instruments DS89C21TM/NOPB is a RS-422 Interface IC Diff CMOS Line Driver and Receiver Pair. The integrated circuit (IC) is capable of sending and receiving digital signals over twisted pair copper wire media. Its differential line driver offers improved common-mode noise rejection performance and improved signal quality on the transmitted RS-422/RS-423 line. The receiver section of the IC is capable of accepting signals from multiple drivers on a shared line, providing multi-point data communication and greatly expanded bus length. Its low power consumption and high operating speed make the DS89C21TM/NOPB ideal for a variety of digital signal transmission applications including industrial automation, process control, and instrumentation.