Abstract: A DTMF generator includes a high gain differential amplifier having a noninverting input, an inverting input, and an output. A first audio oscillator connects to the inverting input of the amplifier via a first series of frequency determining components. A second audio oscillator connects to the amplifier output via a second series of frequency determining components. The noninverting input of the amplifier connects to ground. A plurality of SPST switches interconnects the first and second frequency determining components, such that when any particular switch is closed, a unique feedback path is established from the amplifier output to the inverting input. This causes a ground potential to exist at the contacts of the particular closed switch thereby forcing both oscillators to turn on.