The standard specifies the character structure to be used for serial-by-bit start/stop and synchronous data transmission systems using the 7-bit coded character set according to DIN 66003 also for the case of the case of the 8-bit-coded character set which is the subject of DIN 66303 and extensions to these coded character sets which are the subject of DIN 66203. It applies to the information trasfer through the interfaces between data terminal equipment (DTE) and data circuit-terminating equipment (DCE) standardized in the series of standards DIN 66020 and DIN 66021.