Here is straight from the acad help file (2007)
Code:
You can enter the following special characters and symbols by entering a control code or a Unicode string. Or in the In-Place Text Editor, click Symbol on the expanded toolbar.
Note Symbols are not supported in vertical text.
Unicode strings and control codes
%%d
\U+00B0
Degree symbol (°)
%%p
\U+00B1
Tolerance symbol (±)
%%c
\U+2205
Diameter symbol ()
To insert the following text symbols, click Symbol on the expanded Text Formatting toolbar or enter the appropriate Unicode string:
Text symbols and Unicode strings
Almost equal
\U+2248
Angle
\U+2220
Boundary line
\U+E100
Centerline
\U+2104
Delta
\U+0394
Electrical phase
\U+0278
Flow line
\U+E101
Identity
\U+2261
Initial length
\U+E200
Monument line
\U+E102
Not equal
\U+2260
Ohm
\U+2126
Omega
\U+03A9
Plate/property line
\U+214A
Subscript 2
\U+2082
Squared
\U+00B2
Cubed
\U+00B3
These text symbols are available in the following True Type (TTF) and SHX fonts:
- Simplex
- RomanS
- Isocp
- Isocp2
- Isocp3
- Isoct
- Isoct2
- Isoct3
- Isocpeur (TTF only)
- Isocpeur italic (TTF only)
- Isocteur (TTF only)
- Isocteur italic (TTF only)