The model 202, sometimes called the D1, was the Bell System's mainstay telephone from 1930 to 1936. The D1 designation referred specifically to the phone's streamlined, oval-shaped base, which featured the company’s first recessed dial, called the 4-type. But the phone is of interest to collectors not so much for its exterior design as its interior circuitry, particularly in the handset. Until the 202, most Western Electric phones sent the recipient's voice, as well as the caller's, into the earpiece, producing a phenomenon known as sidetone. Model 202 phones had anti-sidetone handsets that sent just enough of a caller's voice into the earpiece to assure them the device was working, but not so much to be distracting. Though a panel of Western Electric designers had selected a number of colors for their new 202, the introduction of these colors was delayed following the effects of the Great Depression. Western Electric was not immune to the downturn, laying off around 80 percent of its employees. Thus, the original 202s were available only in black, known as a “rubber finish japan” for its shiny, lacquer-like appearance. Eventually, the company added ivory, grey, bronze, gold, and oxidized silver to the phone’s palette. By 1936, the new model 302 telephone was introduced to replace the 202. Part of the redesign was a sleeker handset, the F1, which eliminated the cup-like mouthpiece on the previous version, the E1. But because so few new telephones were produced during World War II, many 202s remained in service for decades. In an attempt to upgrade its old phones for customers who did not want to invest in new ones, Western Electric often swapped out the handsets, replacing the clunkier E1s with more modern F1s. That's why so many 202s today appear to be hybrids of 302 and earlier D1-era designs. In the early 1950s, Western Electric reissued its 202 model as an “Imperial” set in an attempt to make use of overstocked hardware. Along with the fancy name change and an updated coiled cord, these 202s were repainted in the latest range of hues. Some had ivory handsets with gold or silver cradles, which the company then advertised as “premium” models, despite their outdated technology.