The output frequencies are produced from data loaded to the device, with a programmable, general purpose, on-chip timer available to indicate the tone transmit periods. A Dual Tone Multi-Frequency (DTMF) output is obtained by combining the 2 independent output frequencies in the integral summing amplifier. This Summing Amplifier output is also available for level adjustment. Tones produced by the FX803 can also be used in the DBS 800 system as modulation calibration inputs and for "CUE" audio indications for the operator. Received tones are measured and their frequency indicated to the Controller in the form of a received data word. A poor-quality or incoherent tone will, after a programmed period, indicate NOTONE. The FX803 is a low-power, 5-volt CMOS integrated circuit and is available in 24-pin DIL cerdip and 24-pin/lead plastic SMD packages.