I am new here . Found this forum while searching around the web looking for am answer to a problem I have. I built a dtmf decoder using a 8870 and then sending the signal from there into a 74154 demultiplexer. My problem is that the pin ( of the 74154) corresponding to the number I send into the 8870 stays low until I put in the next number then it goes back high again. I would like to have it so that it only stays low as long as it is actually recieving the tone then have them all go back high as soon as I stop sending the tone. I am not sure of how to post a schematic here but it is built right according to the reccomendations on the data sheets of the two chips. It works pretty well, but I would just like to make the 4 pins ( from the 8870)somehow ground out after the tone isnt being recieved anymore . I hope I explained it well enough and I hope that someone here can help me get rid of my headache. Thanks a bunch..