HP Forums

Casio sued and won:

https://www.marks-clerk.com/insights/sha...or-design/

Now, I wonder what happens with all HP39g, gs, gII, g+, etc. calculators that are selling on Aliexpress as "new"? Are they illegal copies too?

Interesting find. I see the IP in question is a 2014 Chinese design patent - so, first you need a design patent that hasn't expired, and then you need to show that it has been infringed.

I note that the case is against both the manufacturer and the seller (presumably the company which commissioned the production and sells to wholesalers) and that although the four-way navigation keys use a slightly different shape, that was not enough to distinguish the copy.

(Generally speaking, IP includes design patents, patents, trademarks, and copyrights, each of which has its own rules. There might be other relevant forms of IP too - perhaps those relating to passing off copies of luxury goods. It's notable that mask copyright on chips has a shorter life than copyright on creative works such as software, so that's two different kinds of copyright.)

Here is an official Casio video comparing original and fake calculators:

https://www.youtube.com/watch?v=7yMfhUpQfKg

In the end of the video, it shows that the fake calculator returns completely incorrect answer.

(06-27-2021 06:34 PM)celltx Wrote: [ -> ]In the end of the video, it shows that the fake calculator returns completely incorrect answer.

To be fair to the fake calculator, equation setup (Newton's method) have 2 solutions.

f(x) = (21+x)/x - 8
f'(x) = -21/x^2

nt(x) = x - f(x)/f'(x) = x - ((21+x)/x - 8) / (-21/x^2) = x - x*(x-3)/3
nt(x) = x       → x = 0 or 3

We should setup equation by scaling away denominator

f(x) = (21+x) - 8x
f'(x) = -7

nt(x) = x - f(x)/f'(x) = x - (21-7x)/(-7) = 3       → x = 3

---

Tips: it is safer to put equation on the stack (without "=" key), before SOLVE
This way, we can recover equation with ↑ key

0 STO X                // guess in X, such that equation does not ERROR
21+X-8X =           // equation now on stack
SOLVE SOLVE       → X = 3

Quite interesting that the copy is using different firmware - this isn't a case of the code or the chip design leaking out or being reversed, it's more a case of making something which supposedly works the same way... but doesn't quite, as it turns out.

But Casio copied a calculators from the famous manufacturer Gaxio, as this video below proves:

(09-06-2021 02:28 PM)Jlouis Wrote: [ -> ]But Casio copied a calculators from the famous manufacturer Gaxio, as this video below proves:

I love that video! In fact I tried to buy a Gaxio but they're almost impossible to find now.

Decades ago, when visiting Thailand, I bought a Faux-lex from a street vendor (~$20).
She was proud to tell me that it had a Seiko movement (implying that it would be accurate and reliable). But on her table I noticed several "Siege" watches as well, so maybe the one I bought had a "Siege" movement as well!
B^)

Next time, if I decide to put a fresh battery in it, I'll try to remember to check to see if there is any indication of who made the movement.