The Teletype Model 33 is an electromechanical teleprinter designed for light-duty office use. It is less rugged and cost less than earlier Teletype machines. The Teletype Corporation introduced the Model 33 as a commercial product in 1963; the machine had originally been designed for the United States Navy. There are three versions of the Model 33: Model 33 ASR (Automatic Send and Receive), which has a built-in eight-hole punched tape reader and tape punch; Model 33 KSR (Keyboard Send and Receive), which lacks the paper tape reader and punch; Model 33 RO (Receive Only) which has neither a keyboard nor a reader/punch. The Model 33 was one of the first products to employ the newly-standardized ASCII code, which was first published in 1963. A companion Model 32 used the older, more established five-bit Baudot code. Because of its low price and ASCII compatibility, the Model 33 was widely used with early minicomputers, and the large numbers of the teleprinter that were sold strongly influenced several de facto standards that developed during the 1960s and 1970s. History Teletype Corporation's Model 33 terminal, introduced in 1963, was one of the most popular terminals in the data communications industry until the late 1970s. Over a half-million Model 32s and 33s were made by 1975, and the 500,000th was plated with gold and placed on special exhibit. Another 100,000 were made in the next 18 months, and Serial Number 600,000, manufactured in the United States Bicentennial year 1976, was painted red-white-and-blue and shown around the country during the last part of that year and the year after. The Model 33 originally cost about $1000, much less than other teleprinters and computer terminals in the mid-1960s, such as the Friden Flexowriter and the IBM 1050. In 1976, a new Model 33 RO printer cost about $600. Early video terminals, such as the Tektronix 4010, did not become available until 1970, and initially cost around $10,000. However, the introduction of integrated circuits and semiconductor memory later that decade allowed the price of cathode-ray-tube-based terminals to rapidly fall below the price of a Teletype teleprinter. "Dumb terminals", such as the low-cost ADM-3A (1976) began to undercut the market for Teletype terminals. Such basic video terminals, which could only sequentially display lines of text and scroll them, were often called glass teletypes ("glass TTYs") analogous to the Teletype printers. More-advanced video terminals, such as the Digital Equipment Corporation