This International Standard specifies a 26-pole connector, including the necessary mateability dimensions and the assignment of contact numbers, for use at the interface between data terminal equipment (DTE) and data circuit terminating equipment (DCE). It is applicable where the functional characteristics of the interface conform to 100 Series definitions in CCITT Recommendation V.24 and the electrical characteristics conform to CCITT Recommendations V.10, V.11, or V.28. It is not applicable to modems for parallel data transmission.