Q: what does § and ± mean?

§ - http://en.wikipedia.org/wiki/Section_sign

± - http://en.wikipedia.org/wiki/Plus-minus_sign

FYI for future questions, this forum is intended for questions about old Apple hardware that precedes the PowerMacs, i.e. hardware from the 1990s and earlier, and doesn't get much traffic. Hence it's not the forum where you'll be most likely to get help with your problem. Normally it will get you the quickest and most applicable replies if you ask questions in the forum for your specific Mac.

Regards.

Yours must not be a US keyboard--none of ours have those characters.

± is "plus/minus" often typed "+/-" on computers until the proper symbol was available. Commonly used in engineering and drafting to denote an allowable tolerence. Example of use:

"The design length of the actuator arm is 105.00±0.1mm."

The other symbol is a section symbol:

http://en.wikipedia.org/wiki/Section_sign