This Recommendation, which should be applied in conjunction with the provisions of Recommendation D.10, sets out the special tariff principles intended for application to the international circuit-switched public data communication service by means of public data networks.
ITU-T D.20-1993 Referenced Document
ITU-T D.20 SPECIAL TARIFF PRINCIPLES FOR THE INTERNATIONAL CIRCUIT-SWITCHED PUBLIC DATA COMMUNICATION SERVICES
ITU-T D.20-1993 history
1993ITU-T D.20-1993 SPECIAL TARIFF PRINCIPLES FOR THE INTERNATIONAL CIRCUIT-SWITCHED PUBLIC DATA COMMUNICATION SERVICES