Garry Garrett's Homepage

Character:

Where the character is a printable character, the character is shown here. When the character is non-printable, some representation is shown in italics (usually a 2-3 letter abbreviation).

Dec:

The decimal (base 10) representation of the character's ASCII code. This is widely used, and in HTML it can be used in a &#999 sequence (where 999 is the decimal value) to pull a given character out of "thin air". This is useful for special characters.

Hex:

The hexadecimal (base 16) representation of the character's ASCII code. This is also widely used. In HTML, you can use %99 (where 99 is the hexadecimal value) in a URL to represent a character (commonly used when that character has a reserved meaning in a the URL syntax).

Oct:

The Octal (base 8) representation of the character's ASCII code. This is commonly used in C programming to pull a given character out of thin air. In your source code you can use \777 (where 777 is an octal value) to represent a character.

Binary:

The binary (base 2) representation of the character's ASCII code. Binary is not commonly used, unless you get into assembly language programming, but I list it here anyway.

Sun:

On Sun keyboards, you can use the "Compose" key to enter a character that does not exist on your keyboard. This is done by hitting the Compose key (lower right hand side of the QWERTY part of the keyboard, next to the right Meta key) and then hitting 2 characters. This column lists the 2 character sequence that you need to enter the character in question. If there is more than one combination, then multiple 2 character sequences are listed on multiple lines. Most of the sequences are pretty intuitive (an A and a " make a �; a C and an O make a �, etc.). This works on most X-Windows programs (shelltool, textedit, mailtool, etc.) but a notable exception is xterm.

On PCs you can hold down on the ALT key, and enter in the ASCII code (in decimal) on the numeric keypad, and when you let go of the ALT key, the corresponding character would be inserted. If you use OEM ASCII or ISO-Latin-1 kind of depends. Most Windows fonts use ISO-Latin-1, but some applications (like Notepad) still display everything in OEM ASCII. At any rate, this is (or was) the Windows equivalent of Sun's Compose key. Here's a page on how to Type Accents and Special Characters (Covers Mac, PCs, etc.). Here's another one for Typing Foreign Language Characters on your Mac or PC. Note: you must use the keypad and not the number keys that sit over the qwerty keyboard. My laptop doesn't have a numeric keypad, it does, however, have a "function" key, and when I hold down on the function key, some of the keys on the qwerty keyboard change their function. 7890UIOPJKL;M,./ all operate as the keypad, so I must hold down both "Fn" and "Alt" to use this method. If your PC lacks a numeric keypad, you may have to do something similar.

For Mac OS X, the conventional wisdom is to fire up a program called "Keycaps". You can learn the key sequences with the meta keys by typing in the keycaps program, which shows you as you hit the various keys (Alt, Meta [open apple], etc.) what symbols will result. Generally speaking, the order tends to be opposite from Sun's Compose key (i.e. you would hit the umlaut key seqence, and then the "A"). You can use Keycaps to teach you the key sequences, but most people's needs are only occasional, so they simply type whatever it is they want to in Keycaps and cut and paste from there into whatever application they want.

HTML:

HTML allows you to put in special sequences of characters that tell the browser to render (if it can) special characters. In addition to the named special characters listed here, any random ASCII character can be generated by ϧ where 999 is the Decimal value of the ASCII code. In URLs, special characters can be represented by %99 where 99 is the Hexadecimal value of the ASCII code of the desired character (helps to avoid reserved symbols).

Description:

A brief description of the character.

ASCII is the American Standard Code for Interface Interchange (the two I's are not a roman numeral 2, many people incorrectly assume that). ASCII was invented for Teletype machines. Originally, only the first 128 characters (0-127) were defined because the high order bit (if you look in the binary column, you'll notice that the first 128 characters have a "0" in as the first digit) was used for a form of error checking called parity. This is commonly refered to as "7 bit ASCII" as it used only 7 of the eight bits.

In today's modern world of communications, this form of error checking is no longer required as it is generally performed at the hardware level or in a communication protocol. This suddenly "freed up" the high order bit allowing 128 "extra" characters. Every hardware vendor came up with their own set of "extended" characters, using them to add characters for non-english languages, characters to draw lines, symbols that 7 bit ASCII didn't include (like cent sign). This became problematic. The International Standards Organization stepped in and decided to come up with a standard 8 bit ASCII. Like a true committee, they didn't come up with a standard, they came up with a collection of standards. Fortunately, one of the many standards that they produced has gained wide acceptance as the defacto standard ASCII. The ISO-8859-1 standard, commonly called, ISO-Latin-1 (it is the first of a couple of standards for Latin based languages - it's character set provides characters for most European based langauages) has become the standard ASCII of the internet. It is the standard character set of the web. Most computer vendors use it as their standard character set for their ASCII based computers. Althought PCs were originally produced with their own non-standard ASCII called CodePage 437 (or simply "OEM ASCII") most Windows (3.x, 95, 98, NT) fonts are ISO-Latin-1.

On a related note, I have a PostScript file that prints out an ASCII chart (of sorts) of all of the standard Level 1 fonts in both their "standard" and "ISO-Latin-1" encodings. You can view it as PDF file or in the orignal PostScript format.

Some IBM computers ( mainframes, AS/400's, etc., and clones thereof ) use a different character set called EBCDIC (The "E" in EBCDIC stands for "Extended", i.e. 8-bit, BCDIC was 7-bit, but most people never even refer to the original BCDIC). I plan on eventually adding EBCDIC to the chart above (or making it's own chart). Converting from EBCDIC to ASCII can be a major issue when moving data from computer to computer. Most methods that are built into a file transfer protocol (FTP for example) tend to be pretty simple minded, for example conerting into 7 bit ASCII. Because of the simple minded approach, these conversion routines rarely have a 1:1 conversion (i.e. two EBCDIC characters might convert to the same ASCII character), thus unless you have relatively simple text, if you convert from EBCDIC to ASCII and back again, you may not get back what you started with. In Unix, the "dd" command is intended to read from tapes, but is happy to read from files as well, and comes with an option to convert from EBCDIC to ASCII, etc. (or vice versa). If you have relatively simple data to convert, the built-in routines work just fine, but if you have anything even slightly complex (like say cent sign); face it, you will have to write your own conversion program or conversion table. I do plan on adding tips and information about converting in the future.

ASCII Art is composing "pictures" using ASCII characters. It is common to include these pictures in your e-mail "signature file" (a file appended to all your e-mails). In order to properly view ASCII art, you will need to use a non-proportional font (one in which each character is the same width - i.e. the width of the character is not proportional to the width of the letter - e.g. Courier). Degraeve.Com has a cgi-bin program called gif2txt to turn a GIF file into an ASCII art. Some ASCII Art, commonly called "ASCIImation", is in the form of "escape sequences", designed to "play" on certain terminals (VT100, etc.) as a form of animation.

Lastly, I have recently become aware of a standard known as Unicode. This is a 16 bit character set with the goal of including all characters from all kinds of different languages. The first 256 characters exactly match those of ISO-Latin-1. Characters are included from a wide variety of current day languages (Chinese, Greek, Hebrew) as well as extinct ones. Unicode appears to be an evolving character set, with current languages included and many characters that are proposed (everything from Heiroglyphics to Klingon). They have charts of all the characters. I'm still trying to understand Unicode because it uses many acronyms that aren't explained very well on any web pages I've found (UTF-8, UTF-7, UCS-2, UCS-4, ...).

I know, I said "lastly", but this is kind of a PostScript of semi-related issues. Wikipedia has some nice pages on Morse Code and the NATO phonetic alphabet (you know, using words to "spell out" connection like a radio or phone, where two letters might sound similar- "C as in Charlie", etc.). I have an HTML redition of Morse Code / NATO phonetic alphabet I'd also like to add a link to somewhere that has the various flags that ships traditionally use to spell out messages.