Rec. ITU-T F.721 (1988) – Basic narrow band videophone service in the ISDN
1 Introduction
1.1 Scope
1.2 Bearer capabilities
2 Description of videophone service supported in the ISDN
2.1 Definition
2.2 Service description
2.3 Applications of the videophone service
2.4 Necessary quality characteristics
3 Intercommunication
3.1 Intercommunication with telephony
3.2 Intercommunication between different videophone services
3.3 Intercommunication with other audiovisual and audiographic services
4 Service operation
4.1 Call set-up
4.2 Call release
4.3 Change of service
4.4 Addressing of terminals
5 Controls and indications
5.1 User guidance
5.2 Additional items
6 Supplementary services