System Behind Characters and Symbols With ALT Key?

[mbrierst]

I understand some of how typing characters and symbols with the ALT key
works. For example, entering unicode by typing the code and then ALT-x. And
I understand how I can type ALT and a four digit code on the numeric keypad
to get stuff on the code page, like ALT-0209 to get a nice Spanish N.

But what the heck is the system behind ALT and a three digit code? When I
type ALT-209 I get a strange symbol and I have no idea where it comes from.
And why is ALT-132 the same as ALT-0228? I can't see any rhyme or reason
behind it. Are the three digit codes just historical or something?

 

[Suzanne S. Barnhill]

Yes. If you open the Symbol dialog in Word and change the display from
Unicode to ASCII (decimal), you'll see the codes you can use with Alt+xxx.
They're useful only for fonts that have no characters above 255.

--
Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA
http://word.mvps.org

 

[mbrierst]

Yes. If you open the Symbol dialog in Word and change the display from
Unicode to ASCII (decimal), you'll see the codes you can use with Alt+xxx.
They're useful only for fonts that have no characters above 255.

Well, that would certainly make sense, but it doesn't seem to be altogether
true. When I go to the Symbol dialog, and change the settings to Courier
font and ASCII(decimal) I see that character 209 is the spanish N, as
expected, and as I get when I type ALT-0209 in Courier. But when I type
ALT-209 I get some other strange character, and I don't see that in the
Symbol dialog anywhere. What's up with the three-digit version of 209?
Where is the list of those characters, or what's the system?

 

[Suzanne S. Barnhill]

Ah, just so. Alt+0209 *is* the ASCII code (Unicode for Ñ is 00D1).

If you select the character you get with Alt+209 and press Alt+X, you get
2564, which is one of the Box Drawing characters. There's discussion of
these at http://en.wikipedia.org/wiki/Box_drawing_characters and a large
chart at http://www.faqs.org/docs/docbook/html/iso-box.html.

IIRC, there were two initial sets of 256 characters, or "code pages," one of
alphabetic characters and the other of graphic symbols. See also
http://www.delorie.com/gnu/docs/emacs/emacs_560.html

I'm sure someone in the .printingfonts NG (to which I'm cross-posting this)
will be more knowledgeable.

--
Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA
http://word.mvps.org

 

[mbrierst]

Ahh... Your comments below have led me to this wikipedia page:
http://en.wikipedia.org/wiki/Windows-1252
which does mention the fact that code page 437 is used on Windows when the
leading 0's are omitted. That matches what I see. I wonder if this is
documented anywhere by Microsoft?

Also, still mysterious is that according to that same wipipedia page, when
you do the leading 0's, you're supposed to get Windows-1252. And it's true
that I MOSTLY get Windows-1252, but there are some characters at the
beginning that don't match up. For example, ALT-0001 gives a symbol very
similar to ALT-218, though not quite the same. And this ALT-0001 character
resists ALT-x to decode it, so no help there. I also wonder if this is
documented anywhere.

 

[Suzanne S. Barnhill]

The first 32 characters (ASCII) are control character that don't print
(things like Backspace, Line Feed, Carriage Return, etc.).

--
Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA
http://word.mvps.org

 

[mbrierst]

Well, I'd certainly expect control characters, that's what the code page
says. But that's not what I get when I type in ALT-0001, ALT-0002, ALT-0003,
etc. I get more things that look like box drawing characters, but not
exactly the same. Some of those low numbers appear to be control characters,
but a bunch show some symbols on the screen.

 

[Suzanne S. Barnhill]

Word often substitutes a box as an "I can't print this" character for
unknown/missing font characters.

--
Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA
http://word.mvps.org

 

[mbrierst]

To be clear, these aren't the boxes that mean "I can't print this". These
are characters that look very much like box drawing characters. Like a lower
right corner, an upper left corner, etc. Try it in word to see if you're
interested.

 

[Suzanne S. Barnhill]

Well, I get boxes for 0001, 0002, and 0003. Should I persevere? Perhaps it
depends on the font? I was using TNR. But if I change to Courier New, I
still get boxes.

Now if I switch to Cambria or Calibri, I get boxes with question marks in
them!

--
Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA
http://word.mvps.org

 

[mbrierst]

Very interesting. I was using Courier (just plain Courier, not Courier new).
I don't have word on this computer so I can't test it now, but I'll probably
try it at work tomorrow with some other fonts.

 

[Suzanne S. Barnhill]

Is the Courier a TrueType font or a printer-resident one?

--
Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA
http://word.mvps.org

 

[mbrierst]

Good question. It looks like it's printer resident. But I still get the
same behavior with Times New Roman, Courier New, and Arial. Something must
be different between our setups. How strange.

Well, at least I've got the basic idea behind the differences between adding
leading 0's and not (code page 437 vs Windows-1252). This last little edge
case is a bit less interesting.