Abstract: A plug-in computer card includes an audio generator circuit having an audio analog output and an enclosure around the audio generator circuit. An audio speaker element is contained within the enclosure, and is in electrical communication with the audio analog output of the audio generator circuit. The audio speaker element is preferably a piezoelectric element fixed to a cover of the enclosure or a loudspeaker mounted within the enclosure. There is an input/output connector fixed to the enclosure and in electrical communication with the audio generator circuit. The card is also provided with a disabling circuit that electronically disables the audio speaker element responsive to an electronic signal.

Abstract: A system has the capability to determine the termination status of a data-communication bus therein. The system includes a source of a bus signal from a bus, a selectively activated current sink that communicates with the source of the bus signal, with a detection activation input, and a source of a detection signal in communication with the detection activation input of the current sink. There is a source of a first reference voltage, and a source of a second reference voltage, the second reference voltage being less than the first reference voltage. A high-termination comparator has an upper voltage input that communicates with the source of the bus signal, a lower voltage input that communicates with the source of the first reference voltage, and a logical high-termination output.