TEXAS INSTRUMENTS MAX232 MAX2321 handbook
Datasheet
The document introduces MAX232, a dual driver/receiver that includes a voltage generator to supply TIA/EIA-232-F voltage levels from a single 5V supply. It can convert TIA/EIA-232-F inputs to 5V TTL/CMOS levels and TTL/CMOS inputs to TIA/EIA-232-F levels. The product features low supply current, ESD protection, etc.
