Abstract: Apparatus for sequentially printing characters along a ribbon or paper tape in response to receiving a sequence of touch tone signals. The apparatus comprises a touch tone decoder and a printer. Included in the touch tone decoder is a dual tone multiple frequency analyzing circuit which receives the touch tone signals and transmits therefrom BCD signals and control logic signals. A select function control circuit is responsive to the BCD signals and the control logic signals to select an ROM memory from a group of ROM memories. A select letter control circuit receives the BCD signals and the control logic signals and addresses the selected ROM memory to produce a parallel multiplex output signal for controlling the operation either of a matrix or a line print head of the printer. Included in the printer is a motor circuit and a control circuit to advance the ribbon or paper tape past the matrix or the line print head.

Abstract: A method and apparatus for separating the two analog component signals which make up a dual tone multiple frequency (Touch Tone) signal, converting the component signals into digital identification signals representative of the component signals, and then recombining the identification signals and developing a digital output signal which corresponds to the particular input signal. The apparatus includes signal separating means for separating the input analog signal into its two component signals, frequency identification decoding means for identifying the two component signals and developing digital identification signals corresponding thereto, and digital logic means responsive to the identification signals and operative to develop particular one-of-sixteen digital output signals which correspond to the particular Touch Tone signal input to the system.