| 摘要 |
An apparatus providing a dynamic virtual service capability in a multi-service communications system is claimed. A dynamic virtual service comprises an associated group of basic services wherein only one of the basic services in the group is active at any time. Basic services comprise a number of service components which are transmitted to the apparatus on one or more of a plurality of different frequency channels. The apparatus comprises a service selection switch for selecting either one of the basic services directly or one of the dynamic virtual services. A dynamic virtual service map is provided that defines for each dynamic virtual service, on a time-varying basis, the currently active one of the group of basic services that comprise that dynamic virtual service. Means responsive to the service selection switch and to the dynamic virtual service map are provided for automatically selecting the currently active basic service of a subscriber selected dynamic virtual service. Finally, the apparatus provides means for receiving and accessing the service components of a selected basic service from the frequency channel carrying those components. According to one embodiment, dynamic virtual service map definitions are periodically re-transmitted to the apparatus on each frequency channel carrying service components of one of the group of basic services that comprise that dynamic virtual channel. Additionally, a "home" basic service may be defined for each virtual dynamic service. When a dynamic virtual service is initially selected by a subscriber, the apparatus initially "tunes" to the frequency channel carrying the service components of that home basic service.
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