The model 500 was the Bell System's mainstay telephone from the 1950s through the 1980s. When it was designed in 1949 by Henry Dreyfuss, whose firm also conceived the WE 302, rotary-dial technology was state of the art. But the phone was in the marketplace for so long that it evolved its internal electronics, if not its external appearance, to incorporate 10 touch-tone keys beginning in 1964 (“star” and “pound” keys would come later). One of the most important dates in the history of the model 500 is 1951, which was the year Western Electric, a subsidiary of AT&T and the sole supplier of household telephones to the monopoly, was forced to license the design of the 500 to other manufacturers. Two companies that manufactured model 500 telephones under license from Western Electric were Kellogg, which by then was owned by ITT, and Stromberg-Carlson, which found it more profitable to reproduce 500s than to build and market its own designs. In the beginning, much like the Model T, the 500 came in any color you wanted, as long as it was black. But by 1953, Western Electric was offering 500s in three shades of ivory, five shades of green, and four shades of red. A collection of blue phones were introduced the following year, and by 1957, WE was even distributing phones in hues of pink, a precursor, perhaps, to its introduction of the Princess phone in 1959. Some of the more interesting models in the 500 series include the 500C, which lacked a dial; the 500P, which had a hooded dial lamp that lit up when the handset was removed from its cradle; and the 502, which had a white “exclusion plunger” that could be lifted when users on party lines wanted a little privacy. Models labeled 554 were essentially 500 desk sets mounted to a wall, and in 1958, Western Electric offered separate speaker and microphone units for hands-free calling.