Abstract: A tone generator is disclosed comprising an LSI controller and read only memory to provide any one of a pre-established set of audio signals to a standard pulse code modulated data stream. This is accomplished utilizing the origination address and destination address that appear on the origination and destination buses in every cycle of data. The origination address designates any one of the pre-established signal patterns stored in the ROM. The designated signal is read onto the data bus by the disclosed signal generating system by reading out the elements of the signal tone stored in the ROM. The predefined tones are stored continuously and regenerated continuously by the controller; thus, each tone is available during each frame cycle to be read out when the origination address calls for the tone. The samples of the tones and signals are stored in the ROM in the digital form they will have on the PCM data bus.