In 1983, Motorola introduced the first cellular telephone in the United States. Called the DynaTAC, this bulky device bears little resemblance to the mobile phones of today. Between then and now, handsets have undergone a dramatic evolution, changing as much in terms of aesthetics as they have on the inside.Flipping outOne of the first major design innovations in cellular phones — besides making them smaller — was the concept of flip-open handsets.