This is based on a wonderful little card Jim Willing used to distribute on the back of CPMUG membership cards. Best thing since sliced bread. Octal has a 0 in front of the numbers, hex has a 0x in front of the numbers, and decimal is just plain black numbers.
Control characters 0-31 (NUL-US) correspond to control keys on the keyboard in the UPPER-CASE section of the chart. for instance, US is Ctrl-_ and SO is Ctrl-N.
Unicode character set matches Ascii from ! up to ~.
The OEM Character set is on 2 fonts used by the cmd shell on PC Windows systems: Terminal and Lucida Console. This is what I use for these pages in blue background with cyan text. Mac users and Linux users will probably not be able to see them correctly and it will come out as monospace, but they will see the unicode fine. The OEM characters don't print correctly on IE7, but they do display correctly, however it does print fine on FF3.