ISO 2110:1989 Preview
Information technology -- Data communication -- 25-pole DTE/DCE interface connector and contact number assignments
This standard was last reviewed and confirmed* in 2002.
*Therefore this version remains current
Specifies the 25-pin connector and assignment of connector pin number at the interface between data terminal equipment and data circuit-terminating equipment or automatic calling equipment. Applicable to voice band modems, public data network facilities, telegraph signal converters, and automatic calling equipment where CCITT Recommendations V.24 and V.28 are valid.