ISO 9543:1989, Information processing systems - Information exchange between systems - Synchronous transmission signal quality at DTE/DCE interfaces

Prescribes quality requirements for serial data transmission at the interface between synchronous transmission Data Terminal Equipment and Data Circuit-terminating Equipment in conformance with the CCITT Recommendations V.24 (telephone networks), X.24 (data networks) as specified in DCEs of the corresponding CCITT-Recommendations. Takes into account the need to have performance cotegories of signal quality depending on the type of interchange circuits.