How to remove Silence from an that has DTMF tones in it?

The input to my file is are the DTMF digits but since it has silence intervals in it, i.e., 'beep',silence,'beep',silence, and due to this silence when fft is taken,The system cannot identify the correct frequencies of dtmf so how can i remove this silence?

Answer 1

[sandeeep jan]

Fs = 8000;
t = 0.25;
N = 1:ceil(t*Fs);
% define DTMF:
R = [697,770,852,941]; % Hz, rows
C = [1209,1336,1477]; % Hz, columns
[Ra,Ca] = meshgrid(R,C); % Hz, all
Rb = 2*pi*(Ra(:)/Fs);
Cb = 2*pi*(Ca(:)/Fs);
T = sin(Rb*N) + sin(Cb*N);
% get user input:
J = '123456789*0#';
% subplot is by row
I = input('Enter keys/s [0:9*#]: ','s');
assert(all(ismember(I,J)),'An invalid key was entered')
% plot and play:
for k = 1:numel(I)
    X = strfind(J,I(k));
    subplot(4,3,X);
    plot(T(X,:));
    xlabel(sprintf('KEY%s',I(k)))
    sound(T(X,:));
    pause(0.5);
end