I was upgrading the images of the VT100 Special Graphics character set used in my online transcripts of the manuals today and I wondered about the VT52 equivalents, which are not shown graphically in any of the manuals that I could find; only the descriptions exist.
However, Fritz Mueller dumped the VT52 character generator ROM some years ago, so I thought I’d take a quick look.
In short, the VT52 Special Graphics look like this:
This is a lazy interpretation of the ROM, using a very similar script to that which I use to process the VT100 glyphs, so I haven’t included the extra scan lines that appear between text lines on the VT52, which is either 2 or 3, depending on whether you’re running at 60 Hz or 50 Hz, respectively. I also haven’t checked the aspect ratio of the characters; the Maintenance Manual provides dimensions for the complete raster which I could use.
Two things strike me as odd about this picture:
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The second glyph is marked as “reserved” in all the manuals I’ve seen, so I have no idea what “cd” is supposed to represent, and whether the same glyph is present in all models of the VT52, and
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The VT52 Maintenance Manual claims that only 7 scanlines are retrieved from the character generator ROM, which is clearly incorrect, as there is a glyph containing a horizontal line for each of the 8 scanlines that appear on the display.