IEEE 1394 Unit Filter Driver Plug Management (Windows CE 5.0)
Several AV/C commands exist for the management of plugs. The base commands are defined in the AV/C Digital Interface Command Set, General Specification, and contain commands such as CONNECT and DISCONNECT. A more recent document, the AV/C Connection and Compatibility Management Specification, contains a collection of more complete commands and precise definitions for managing both plugs and connections between subunits. The Windows CE implementation of IEEE 1394, and AVC_UNIT in particular, supports only the first set of commands.
AV/C plugs can be external plugs, serial bus plugs, or subunit plugs. An external plug is a physical connector on a device. This is similar to an audio out plug on a consumer electronics device.
A serial bus plug is an ISO/IEC-61883 concept. It represents an endpoint for streaming communication. Serial bus plugs are common to the unit; all subunits within share the same collection of serial bus plugs. They share the same set of plugs in that any plug number is the same plug for all subunits. They do not necessary share access to the same plugs.
A subunit plug is an AV/C concept. The subunit designer defines subunit plugs, and they can carry different meaning from subunit to subunit. The only modules that actually can make interpretations from subunit plug identifiers are virtual subunits. To all other modules, a subunit plug is merely an abstract number referring to some conceptual source or destination point inside of a subunit.
The IEEE 1394 Windows CE implementation, and AVC_UNIT in particular, supports only serial bus and subunit plugs. External plugs are not supported.
Send Feedback on this topic to the authors