University calculators

[edryer]

I think the 991 (D) EX was/is aimed at the pre University Mathematics market (mostly High Schools).

As such regional variations of the Calculator exist restricting various functionality after negotiations with various educational authorities.

This is more of a new thing I think with modern School calculators, firmware is modified depending on market, in Casio's case D Germany, AU Australia and so on... these are then appended to the model number somehow such as:

FX-991E X (International English Version)
FX-991?? X (Australian version, some restrictions apparently) - not sure on this model
FX-991DE X (Germany) - this apparently has more functions in firmware than the 991E X such as GCD/LCM/Int/Intg shifted functions on the keyboard (and as you say, Graphing export restrictions)
FX-991CN X (China) - Chinese keyboard
FX-JP900 (Japanese variant of 991) - Japanese Keyboard


On another note I am using a FX-85WA which is a (1998) 2-line Basic Scientific and find it a nice calculator, but it lacks anything beyond basic scientific functions, when the 991EX comes it will be interesting to compare them.