Question 9/III - General tariff and accounting principles for the different public data communication network interworking options (continuation of Question 9/III studied in 1985-1988) (To be studied in liaison with Study Groups I and VII.) What Recommendations are appropriate to guide the development of tariff principles for services that involve interworking between different types of public network? Reasons for the study For the study of this Question, attention should be given to the following items: 1. An ongoing review of the requirement for guiding principles resulting from the possible provision of international public data network services offered by means of interworking between networks (e.g. packet and circuit). 2. Possible development of guiding principles allow the Working Parties studying interworking tariff options to address interworking within specific service applications in a cohesive and unified manner. Guiding principles are also of assistance to other Study Groups where the study of interworking forms part of their work programmes.