Description and Scope

The IS-105EfA-105 specification is designed to allow consumer electronic devices such as televisions, VCRs, and other receiving devices (called in this document "Receivers") to be connected to various external devices (called in this document "Decoders") via the Decoder Interface multi-pin connector. This connector provides video, audio, and control channels that may be shared by all devices. A Receiver also provides a separate "IF output" from its cable compatible tuner that may be used by a Decoder. All of the signals on the multi-pin connector are designed to be "bussed," as described in IS-105.1. That is, the signals are extended to multiple devices that share the signals provided by the Decoder Interface. This architecture allows all devices sharing an interface to interact with each other via a control bus and to share audio and video. In addition, the control bus allows the audio and video Lines to be shared among multiple sources. The IF output may also be shared by multiple Decoders. IS-105.1 specifies the physical and electrical interface and this document PIA-105.2) specifies the control system.

The Decoder Interface system provides the access control and features currently provided by "set top boxes" in a more compatible way. Compatibility is defined as the User's ability to transparently use the functionality of both the Receiver and Decoder. The access control and features of Decoders may be integrated into Receivers. The features of Receivers (which provide various ways to manipulate and present video and audio to the User) are not hindered by attached Decoders. This requirement demands a high level of interactivity between devices on this interface, thus enabling Receivers and Decoders to operate as a well coordinated system.

The bus aspect of this environment satisfies the needs of the cable industry in that multiple decoders, e.g. descramblers and electronic program guide (EPG) boxes, can simultaneously interact to present modified video to a receiver. At the same time, the bus aspect allows boxes from different outside networks, such as cable and direct broadcast satellite (DBS), to share access to receivers. This greatly simplifies the operations required by the receiver user when switching from network to network or from service to service from within a single network.

Decoders provide access control of programming typically by descrambling video and/or audio that is provided by the Receiver's IF output (or elsewhere). If a scrambled channel is selected by the User, then a Decoder may provide descrambled video and/or audio to the Receiver with no additional action needed by the User.

Features provided by Decoders may require a User to directly interact with the Decoder. The Decoder Interface allows a Decoder to utilize a Receiver's user interface to interact with the User. Specifically, two different methods are provided (User Command Interception and Addressed Remote Control) whereby commands from the Receiver's normal remote control and/or one provided especially for a Decoder can communicate directly with the Decoder. Since the Decoder Interface supports multiple Decoders, the User is provided a standard facility in Receivers to specifically activate a group of Decoders. Ultimately, the User is in control of the system.