RS-449 defines functional/mechanical
interfaces for DTEs/DCEs that employ serial binary data interchange and
is usually used with synchronous transmissions. It identifies signals (TD,
RD, etc) that correspond with the pin numbers for a balanced interface on
DB37 and DB9 connectors. RS-449 was originally intended to replace RS-232,
but RS-232 and RS-449 are completely incompatible in mechanical and electrical
specifications. Following are the common or standard wiring pinouts for
Serial Data Transmission cables.