EIA-232-D is consider the DTE/DCE interface standard most commonly used in North America (as well as Japan, South Korea, and Taiwan). EIA refers to the Electronic Industries Association.
The predecessor of EIA-232-D, called RS-232-C (the RS was for “Recommended Standard”) was released in 1969, and was primarily used for the interface between DTEs and modems. EIA-232-D is now used for many other applications (e.g., connection to digital DCEs or LAN interface units). EIA-232-E, a 1991 revision, adds optional features to EIA-232-D bringing it into alignment with ITU-T (formerly CCITT) standards V.24 and V.28.