Specifies the character structure to be used for serial-by-bit start/stop and synchronous data transmission systems using the internationally standardized 7-bit and 8-bit coded character sets and extension to these coded character sets. It also specifies the parity sense to be used with the 7-bit coded character set. It applies to the information transfer through the interface standardized by CCITT and IEC/ISO between the data terminal equipment, DTE, and data circuit-terminating equipment, DCE, as defined in the relevant CCITT V and X series recommendations. Technically identical with ISO 1177:1985.