US Patent 7350889 Printer with loudspeaker interface

A printer includes a loudspeaker that announces error messages and the like. The error messages are stored as sound files in an onboard memory device. A central processor communicates with a speaker interface circuit by means of a data bus. A DMA controller is provided that mediates the transfer of instructions from the processor to the speaker interface and to a number of functional circuits that are also coupled to the bus. The speaker interface is equipped with a FIFO circuit that is responsive to DMA controller mediated transfer of sound files from the memory. In order to initiate the playing of a sound file the processor simply programs a DMA channel of the speaker interface.