Recommendation I.241.5 (11/1988): Teleservices supported by an ISDN: Videotex
recommendation/international standard from the International Telecommunication Union
ITU Telecommunication Standardization Sector
Teleservices supported by an ISDN: Videotex
Recommendation F.300 (11/1988): Videotex service
Recommendation I.220 (11/1988): Common dynamic description of basic telecommunication services
Recommendation I.240 (11/1988): Definition of teleservices
Recommendation I.430 (11/1988): Basic user-network interface - Layer 1 specification
Recommendation I.431 (11/1988): Primary rate user-network interface - Layer 1 specification