ITU-T Rec. I.520 (11/1988) – General arrangements for network interworking between ISDNs
1 Introduction
2 Scope
3 Required information and information handling
4 Description of ISDN-ISDN interworking configurations
5 Interworking functions
6 Functional interworking requirements for data transmission services
7 References
APPENDIX I (to Recommendation I.520) – ISDN connections involving restricted 64 kbit/s transfer capability