Article 1
1. This Decision shall apply to data terminal equipment intended to be connected to public circuit switched data networks and ONP leased circuits using a CCITT Recommendation X.21 interface and falling within the scope of the harmonized standard identified in Article 2 (1) of this Decision. 2. This Decision establishes a common technical regulation covering the technical characteristics (electrical and mechanical interface requirements and access control protocol) to be provided by terminal equipment using a CCITT Recommendation X.21 interface, or at an interface physically, functionally and electrically compatible with CCITT Recommendation X.21 but operating at any data signalling rate up to, and including, 1 984 kbit/s.