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.