Scope and field of application This ETS refers to the low layer protocols to be used in the Integrated Services Digital Network (ISDN)@ as defined in CCITT Recommendation T.90 [1] together with ETS 300 080 [2]. This ETS specifies the end-to-end protocols to be used between two end systems as defined in CCITT Recommendation T.62 [3]. In addition@ it defines the octet-string to be interchanged based on the coding scheme@ as defined in CCITT Recommendation T.61 [4]. This ETS gives a general tool for a manufacturer-independent compatible text communication between end systems over the ISDN@ based on the Telematic protocol stack.