receivers. The pinout matches the DB9S connector design in order to decrease the part count, reduce the board space required and allow easy interconnection of the UART and serial port connector of IBM PC/ATTM and compatibles. The bipolar circuits and processing of the ST75285 provides a rugged low-cost solution for this function at the expense of quiescent power and external passive components relative to the ST75C185. The ST75285 complies with the requirements of the EIA/TIA 232-E and ITU (formally CCITT) v.28 standards. These standards are for data interchange between a host computer and peripheral at signalling rates up to 20k-bits/s. The switching speeds of the ST75285 are fast enough to support rates up to 120K-bits/s with lower capacitive loads (shorter cables). Interoperability at the higher signalling rates cannot be assured unless the designer has design control of the cable and the interface circuits at the both ends. For interoperability at signalling rates to 120 K-bits/s, use of EIA/ITA-423-B (ITU v.10) and EIA/ ITA-422-B (ITU v.11) standards are recommended. It allows space saving in applications where two ST75185 are needed.