Question 22/III - General charging and accounting principles for non- voice services provided by interworking between the ISDN and existing public data networks (continuation of Question 22/III studied in 1985- 1988) (This Question should be studied in liaison with Study Groups I, VII, IX, XI and XVIII.) Reasons for the study Considering (a) that during the transition period, it is essential that administrations provide interworking between existing public data networks and the ISDN in order to continue providing users with non- voice services; (b) that administrations should be entitled to recover the costs associated with the interworking between the ISDN and other public networks, What charging and accounting principles are appropriate for non-voice services in the case of interworking between the ISDN and existing public data networks? The study of this Question should cover the establishment of charging and accounting principles applicable for remuneration of interworking facilities provided by the origin, transit or destination administration.