Write code in MATLAB that accepts a character corresponding to one of the above buttons

and generates the appropriate dual$-$tone frequency. You can test your program

by comparing the tones to the tones generated by the telephone $($or by using an

autodial program with the modem on you computer$).$

Finally, write code that records a tone from the microphone and determines the

number. The code should perform an FFT on the signal, and from the prominent

peaks, determine the number. You can test this code by placing the microphone

of the sound card next to the ear piece of the telephone and pressing various

keys.