The M-993 is a monolithic CMOS integrated circuit designed to generate multifrequency (MF) tone pairs for use in trunk signaling. The tones generated conform to CCITT R1 signal recommendations and to AT&T MF standards. The M-993 permits design engineers to implement a highly accurate MF sender with a minimum of space, power, and added components. The accuracy of the tone frequencies is assured through use of an easily obtained 3.58 MHz color burst crystal or an external 3.58 MHz clock source.