Specifies the 15-pole connector and the assignment of contact numbers at the interface between data terminal equipment (DTE) and data circuit-terminating equipment (DCE) where CCITT Recommendations X.24, X.26, and X.27 are applicable. Provides the dimensions of the connector housing, as well as the recommended means of providing a locking device (latching block) and connector shielding. This Standard is identical with and has been reproduced from ISO 4903:1989.