from the article:

"At the request of the state education department two years ago, Texas Instruments had disabled the decimal-to-fraction key and left it blank on calculators intended for middle school students."

If i read this the right way Ti didn't disable it, but they removed the 'f <-> d' text from the keyboard. This is a shifted feature: you have to press 2nd then '<-' (if you look at the big image of the calc on ti's site you'll see what I'm talking about.) My guess is that these are the two keys.

Do you think they were really that lazy? And wouldn't somebody have figured out a long time ago? Hmm. I suppose you might be right.

>> figured out that by pressing two other keys

That makes it sound like it wasn't 2nd+f<-->d.

>If i read this the right way Ti didn't disable it, but they removed the 'f <-> d' text from the keyboard.

It sounds to me like they did remove the text, but also removed the contact underneith. But as other people have said, it might be possible to replicate the same signal from the keyboard using other keys. It doesn't sound like they changed their software, just the hardware.

I think that rewriting the (relativel small) ROM would have been too much work for 11000 calcs. Im guessing the hardware thing is correct

I agree very much

From the picture on the article: (See WEB PAGE link)
It looks like it was just hitting 2nd+Backspace to activate the F<-->D feature, whereas the new model has the backspace key completely disabled.

Well, I wonder how they would have solved the problem if the two keys involved one of the essential keys, like a number or operation key. Surely they wouldn't have disabled those? :-)

i used to have my dad's old calculator, i think it was a ti36, and i discovered on accident that if i slapped the calculator with my hand, the calculator would undergo some sort of self-test. i later discovered that presssing a certain four buttons would trigger the same response, and i dont know if it's on purpose or not.
so i think this kid pressed two keys simutaneously and somehow the calculator glitched and dec>fraction was executed

On a TI-30x Solar, you can hold the a_b/c, 1, 2, and 3 keys simultaneously, and then press ON/AC. Results in the calculator going into some sort of test mode (also, holding 4, 5, 6, 7, 8 and 9 and hitting ON/AC also did a different test if memory serves.)

Does this work for the TI-34 II or TI-30X Battery ?

Last time I checked, it doesn't work on a TI-30 battery. No clue about a TI-34

I don't have a TI-30X Solar. So I'll go to Wal-mart and use the one on display.

Many devices, such as digital wristwatches, seem to have a key combination that will cause them to reset. I had a Radio Shack electronic draw poker handheld game once, and I discovered I could reset the game and my score anytime I wanted by pressing two keys at the same time.

I also had an electronic English/Spanish translater where pressing multiple keys at once would cause the LCD to glitch out as long as the keys were held (but it otherwise worked normally). I seem to recall playing with an old desk calculator of some sort (with some type of lighted display) when I was very little, and when multiple keys were pressed something similar happened.

Yeah, I heard about it on Attack of the Show.

On a calculator (say, for example, a TI-89), there isn't a separate wire going to every button (there isn't space for all that wiring). Instead, the keyboard is divided into "rows" and "columns" with a sensor to determine whether any key in a row, or any key in a column, is pressed. (Note that these sometimes, but don't always line up to the actual rows and columns on the keyboard). When a single key is pressed, the calculator sees one row and column active and knows which key that is. When a second key is pressed at the same time, it can figure out what key that is by taking the set of rows and columns active, and if there are two rows or two columns active at the same time using the one which wasn't on before. But if you press *three* keys at once, it's not always possible to unambiguously determine what the third key was. Start by pressing two keys (call them A and B) in the same column, and then a third key C in the same row as A. Both C and the key in the column of C and the row of B will be detected as pressed, because it's impossible to tell which one it really was.

But that's three keys, and the article said it was only two, so how does that work? Well, with the rows-and-columns system it's always possible to figure out what's going on when there are two keys down, but the hardware to actually do it is actually pretty complicated. So some cheapo calculators skimp; they just say, if there are two columns active use the first one, and if there are two rows active use the second one. (That means you can't press two keys at once and have it read them correctly, which is why I can't stand those cheapo calculators.)

(continued in first reply due to maximum message length)

So if the key you want to press is physically disconnected, all you have to do is press a key which is in the same row, and a key which is in the same column, but above (if higher keys take precedence) or below (if lower keys take precedence), and it'll think you pressed the wrong key. Then all you need to do is find keys in the right positions which don't do anything important, and, wham, you just pressed a key that your calculator doesn't have.

I don't actually have one of these calculators on hand to test, but I'm 99% sure that's what happened. (Mainly because that's the only scenario I can think of which would work; I certainly can't imagine TI would have another key combination programmed in, and this seems plausible). Looking at the picture, if the rows and columns are wired in the obvious way, then 2nd, (+/-)+2nd should do it. If someone actually has a TI-30Xa SE to try, please reply.

Bah, stupid max message length; I posted the reply to myself, but it hasn't appeared (even though the original message appeared instantly). The form won't let me repost because it says it's a dupe, but it's been a couple minutes. and really has the appearance of being lost.

I believe the max message length could be a least a little less restrictive.

I agree completely. At my work (ToysRUs) We have these hand-held devices called "Saphires" and their screens look just like ti-83's. Anyway they probably had the same glitch when they were in R&D because whenever you hit two keys and once, the thing beeps and a screen comes up that says you tried to push multiple keys at once. I guess that was their lazy way of debugging the multiple key glitch. Anyway I thot the same exact thing when I first read the article.

)>-TiAtari-<(

The two keys to convert from decimal to fraction on a TI-30 IIS calculator are 2nd and PRB. Put in the decimal you want to convert, and hit 2nd, then PRB and then = and it will automatically tell if it is a decimal or fraction and convert it to the opposite. Try it yourself! Paffah.

Actually, it was 2nd + <--

Oops, posted twice.