ITU I.251.1:1992
ITU I.251.1:1992 Direct-dialling-in Enables a user to directly call another user on an integrated services private branch exchange or other private system without attendant intervention.
Table of Contents
1Definition2Description
2.1Generaldescription
2.2Specificterminology
2.3Qualificationsontheapplicabilityto
telecommunicationservices
3Procedures
3.1Provision/withdrawal
3.2Normalprocedures
3.3Exceptionalprocedures
3.4Alternativeprocedures
4Networkcapabilitiesforcharging
5Inter-workingrequirements
6Interactionwithothersupplementaryservices
6.1CallWaiting
6.2CallTransfer
6.3ConnectedLineIdentificationPresentation
6.4ConnectedLineIdentificationRestriction
6.5CallingLineIdentificationPresentation
6.6CallingLineIdentificationRestriction
6.7ClosedUserGroup
6.8ConferenceCalling
6.9Direct-Dialling-In
6.10Calldiversionservices
6.11LineHunting
6.12Three-PartyService
6.13User-to-UserSignalling
6.14MultipleSubscriberNumber
6.15CallHold
6.16AdviceofCharge
6.17Multi-LevelPrecedenceandPreemption
6.18Priority
6.19MaliciousCallIdentification
6.20OutgoingCallBarring
6.21ReverseCharging
6.22Sub-addressing
7Dynamicdescription