Technologies de l'information — Utilisation du protocole X.25 de couche de paquet conjointement avec X.21/X.21 bis pour fournir le service de réseau OSI en mode connexion

Applies to environments including a CSDN and an ISDN terminal adaptor complying with recommendation X.30 which provides an X.21 access. Provision is achieved by specifying the mapping of the CONS primitives and parameters to and from the elements of the protocols used (X.25 PLP and X.21).