VT52

The VT50 is a CRT-based computer terminal that was introduced by Digital Equipment Corporation (DEC) in July 1974. It provided a display with 12 rows and 80 columns of upper-case text, and used an expanded set of control characters and forward-only scrolling based on the earlier VT05. DEC documentation of the era refers to the terminals as the DECscope, a name that was otherwise almost never seen. The VT50 was sold only for a short period before it was replaced by the VT52 in September 1975. The VT52 provided a screen of 24 rows and 80 columns of text and supported all 95 ASCII characters as well as 32 graphics characters, bi-directional scrolling, and an expanded control character system. DEC produced a series of upgraded VT52s with additional hardware for various uses. The VT52 family was followed by the much more sophisticated VT100 in 1978.

The VT50 is a CRT-based computer terminal that was introduced by Digital Equipment Corporation (DEC) in July 1974. It provided a display with 12 rows and 80 columns of upper-case text, and used an expanded set of control characters and forward-only scrolling based on the earlier VT05. DEC documentation of the era refers to the terminals as the DECscope, a name that was otherwise almost never seen. The VT50 was sold only for a short period before it was replaced by the VT52 in September 1975. The VT52 provided a screen of 24 rows and 80 columns of text and supported all 95 ASCII characters as well as 32 graphics characters, bi-directional scrolling, and an expanded control character system. DEC produced a series of upgraded VT52s with additional hardware for various uses. The VT52 family was followed by the much more sophisticated VT100 in 1978. ====Cursor positioning==== The code was used to position the cursor anywhere on the screen, using two parameters representing the X and Y coordinates of the cursor position, with the upper left corner of the screen being position 1,1. These numbers were sent as ASCII characters of that value, adding 31. For instance, to position the cursor at column 30 and line 20, you would add 31 to each value to get 61 and 51, then look up those ASCII characters, and . The complete command would then be (note the row, column ordering, not X, Y). Adding 31 ensures that the characters are shifted out of the control range into the printable character range, so they will transmit properly. ====Terminal identifier codes==== The command allowed the host computer to identify the capabilities of the terminal. There were eight possible responses. ====Printer codes==== Several additional codes were used with the optional printer/copier: ====Graphics mode==== The VT52 and VT55 included two characters sets, ASCII and "graphics mode" which switched out the lower case characters and some punctuation with new characters useful for the display of math. Unusual were glyphs for fraction numerators which could be combined with subscript numbers to produce things like , and scan lines allowing a function to be plotted with 8 times higher vertical resolution than text. ===Citations=== ===Bibliography===

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