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A Chart, If You Can Read It

The last couple of evenings I’ve been working at fulfilling a promise I reneged on ten years ago. Somewhere in the text of the second edition of Assembly Language Step By Step (which I was writing in the summer of 1999) I promised readers an ASCII chart as one of the appendices. I then plum forgot, and the book appeared in 2000 without that appendix. I still get emails from people asking me where they could find the chart, and have to reply in my best sheepish email voice that no chart exists anywhere in the book.

So this time I thought to put things right. I sat down in front of InDesign and figured out an ASCII chart format for the full 256-character extended set, and drew me an ASCII chart. For the encoding I used Code Page 437, which is what they now call the IBM PC ROM character set. Whether they could name it or not, CP437 was much beloved of DOS text-mode programmers, with all four card suits and more box-draw characters than anybody ever knew what to do with. The chart will fit comfortably (if snugly) on a single page in what we in publishing call “computer trim,” and I consider it a complete success, at least if you have good eyesight or a set of readers within easy reach.


As best I can tell, there is no encoding option available for Konsole (or any other Linux terminal emulator that I have) for Code Page 437. As close as I’ve come is IBM-850, which has fewer box-draw characters and more non-English alphabet glyphs. Of course, once you have a chart, it’s no big deal to find a new set of glyphs and sub them in, which is what I’ll be doing in coming days. In the meantime, if you have any use at all for a CP437 ASCII chart, here it is. I’ll post the one for IBM-850 when I finish it. Ten years late, I guess, but better late than never.


  1. Tom R. says:

    Great Chart Jeff. I really like the decimal and hex values in the box. I used the CP437 characters extensively back in the old green screen days.

    Of course I had to keep an EBCDIC chart handy too since I was about 80 percent mainframe and 20 percent PC back then! Oh, and don’t forget about the IBM Packed number format where they stuffed two digits in 8 bits. Just to round things out there was of course Baudot, which I am sure you remember from RTTY! I also had a chart for punch cards which I learned to read pretty well since they never bought new ribbons for the key punch machines! I guess things HAVE gotten somewhat simpler in some ways.

  2. Andrew from Vancouver says:

    I used to appreciate having an ASCII chart in the back of a technical book… of course, I still have memorized all the special ones that come up a lot… back then, I also knew the line drawing codes.

    Nowadays, I google for ascii chart and for years the first hit as been:

    and I haven’t needed anything else. I prefer this layout for the decimal, hex, octal conversions, and even oh so modern HTML escaping.

  3. Darrin Chandler says:

    A good ASCII chart is a wonderful thing to have. I always knew I could find one in the back of the Norton book or in the Turbo/Borland Pascal book, and I always kept them handy.

    These days I can “man ascii” or look in /usr/share/misc/ascii on OpenBSD, which can be nicer than a printed chart sometimes. /usr/share/misc/ascii is easily program parsed, and includes octal as well.

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