The RS-449 specification, also known as EIA-449 or TIA-449, defines the functional and mechanical characteristics of the interface between data terminal equipment and data communications equipment.
The electrical signaling standards intended for use with RS-449 are RS-422 for balanced signals, and RS-423 for the unbalanced signals, with data rates to 2 Mbit/s. The standard specifies DC-37 and DE-9 for the primary and secondary data circuits. Though never applied on personal computers, this interface is found on some network communication equipment. The full title of the standard is EIA-449 General Purpose 37-Position and 9-Position Interface for Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange.
EIA-449-1 was rescinded in January, 1986. Superseded by EIA/TIA-530-A, the final version EIA-449-1 was withdrawn in September, 2002.