To make a Red Box from a Radio Shack 43-141 or 43-146 tone dialer, open the dialer and replace the crystal (the largest shiny metal component). The exact value needed is 6.502457409Mhz. Unfortunately, that crystal is not commonly manufactured. A crystal close to that value will create a tone that falls within tolerances. The most popular choice is the 6.5536Mhz crystal. When you are finished replacing the crystal, program the P1 button with five *'s. That will simulate a quarter tone each time you press P1.