As technology advanced rapidly over the course of the 20th century, the telephone industry went through several transformations. From Strowger switches to rotary dials, the Bell company continually experimented with inventive ways of making phone calls. In 1963, AT&T’s patented “Touch Tone” technology changed the telecommunications industry forever. The Dual Tone Multi Frequency signals used by these push button phones could make phone calls, control voicemail machines, and even insert local TV ads into national broadcasts. This episode features interviews with author Annabel Dodd and telephone aficionado Jim Hebbeln of the Telecommunications History Group.