This is one terrible machine. The keys are of the same mod as the TI-55-II and are plain AWFUL.

The BA-54 came soon after and is a much better to use machine than this one. Recommend not paying any $$ for this thing. :-)

How do I really feel?

One other thing. The BA-55 can use the PC-200 printer originally aimed at the TI-66.

If you have a BA-55 where the keys work (as Eddie seems to have) you are very lucky!

(02-19-2018 08:57 PM)Eddie W. Shore Wrote: [ -> ]Texas Instruments' entry into the programming financial calculators. Good for basic calculations and quick and simple programs, but didn't dethrone the HP 12C.

Link: http://edspi31415.blogspot.com/2018/02/r...ba-55.html

Thanks for the great review as always Eddie.

I however agree with Gene in that I think you where very lucky with the keys!

When I went to school in 1985 (when I was around 16) half my class had a Casio fx-180p, and the other half TI-57 (I got first to use a better HP calculator three years later at high school and university).

I think the TI57 is very closely realted to your financial BA-55. The latter half of the class with the TI-57 often swore loudly during math and physics lessons about wrong keypresses (either none, or double), and quite often also about battery contact problems, while we Casio users never had that problem (we however had to use electrical tape to keep the very poorly designed battery door and calculator together).

Good times!

Now to my question; why does the BA-55 have an [x<>y] key, and why is the TI-57 power key [y^x] instead of [x^y], as none of them are RPN calculators (like HP)?

Very strange, and I can not understand why!

The BA-55 has the [x<>y] key to:

1. Allow for bi-variate data entry: (x data [x<>y] y data [Σ+])

2. In two variable statistical analysis, pressing [x<>y] switches between standard deviation of x and standard deviation of y [σn-1]. This also applies for population deviation [ σn ].

3. The key also switch operands. This could be useful in correcting the order of the arguments in subtraction and division operations. Example: I want to calculate 78 - 26 but enter 26 - 78 by mistake:

26 [ - ] 78 (display: 78)

[x<>y] (switches the operands, display: 26)

[ = ] (result: 52, 78 - 26)

Regarding the preference of y^x instead of x^y, I honestly have no idea.

(02-19-2018 09:39 PM)Gene Wrote: [ -> ]One other thing. The BA-55 can use the PC-200 printer originally aimed at the TI-66.

If you have a BA-55 where the keys work (as Eddie seems to have) you are very lucky!

Then I am lucky indeed. I only paid $10, and a pouch and the small booklet came with it.

(02-20-2018 01:41 PM)Eddie W. Shore Wrote: [ -> ]The BA-55 has the [x<>y] key to:

1. Allow for bi-variate data entry: (x data [x<>y] y data [Σ+])

2. In two variable statistical analysis, pressing [x<>y] switches between standard deviation of x and standard deviation of y [σn-1]. This also applies for population deviation [ σn ].

3. The key also switch operands. This could be useful in correcting the order of the arguments in subtraction and division operations. Example: I want to calculate 78 - 26 but enter 26 - 78 by mistake:

26 [ - ] 78 (display: 78)

[x<>y] (switches the operands, display: 26)

[ = ] (result: 52, 78 - 26)

Ahh. That explains it. Thanks!

Looked very RPN-like at first.

(02-20-2018 01:41 PM)Eddie W. Shore Wrote: [ -> ]Regarding the preference of y^x instead of x^y, I honestly have no idea.

Private guess and speculation; I wonder if they looked at HP calculators, and their buttons (it makes sense as a post-pix calculator, but not as in-fix), but not thinking too much about it?

I note that on newer TI calculator it is correctly (to be algebraic calculator) renamed to [x^y].

Trivia question: I wonder when (year? calculator model) TI changed their mind and went from printing [y^x] to [x^y] on the power key?

(02-19-2018 09:39 PM)Gene Wrote: [ -> ]One other thing. The BA-55 can use the PC-200 printer originally aimed at the TI-66.

If you have a BA-55 where the keys work (as Eddie seems to have) you are very lucky!

Interesting! Never seen one IRL.

The P200 printer, is that TI's answer to HP's 82240A/B (or perhaps vice versa if TI was first)?

Is the printing technology about the same?

Does it connect over IR, or some serial interface?

(02-20-2018 09:54 PM)martinot Wrote: [ -> ]Trivia question: I wonder when (year? calculator model) TI changed their mind and went from printing [y^x] to [x^y] on the power key?

Don't know about TI but HP went from x^y (HP 35) to y^x (HP 80) in 1973.

What TI models have X^Y before 1990 or so?

I can't think of any.

?

I don't recall TI ever having the power key marked [x^y].

(02-20-2018 10:46 PM)Massimo Gnerucci Wrote: [ -> ] (02-20-2018 09:54 PM)martinot Wrote: [ -> ]Trivia question: I wonder when (year? calculator model) TI changed their mind and went from printing [y^x] to [x^y] on the power key?

Don't know about TI but HP went from x^y (HP 35) to y^x (HP 80) in 1973.

Which makes sense (from an RPN perspective, and the order of arguments on the stack).

(02-20-2018 11:06 PM)Gene Wrote: [ -> ]What TI models have X^Y before 1990 or so?

I can't think of any.

?

Just curious; when did they change that, even if it was after 1990?

(02-21-2018 03:00 AM)Eddie W. Shore Wrote: [ -> ]I don't recall TI ever having the power key marked [x^y].

I just see that on some current calculators, TI have changed from the old [y^x] button to a [X^□] button (which I think makes more sense on an algebraic calculator, if you think about the order of the arguments).

Here is a comparison between the current HP calc 35s and current TI calc 36X-Pro:

This looks very logic (to me at least) as 35s is RPN and 36X algebraic.

I think I have also seen just [^] on some current graphing TI calculators, and on some others TI's the classic algebraic version [x^y] (even if I do not remember which TI models).

Yeah, all bets are off once the TI graphing models came out with the TI-80. I just don't pay much attention to any of the TI's after that :-) so I don't know if they went x^y or just ^ etc. after that point.

However, before then on a non-BASIC machine, I don't know of any TI models that were X^Y.

(02-21-2018 09:11 AM)martinot Wrote: [ -> ]I just see that on some current calculators, TI have changed from the old [y^x] button to a [X^□] button (which I think makes more sense on an algebraic calculator, if you think about the order of the arguments).

Good catch, I missed that one, Martinot!

Speaking of the TI-36X Pro, what is up with the arithmetic operation keys being silver on silver? That has always bugged me on that model.

(02-21-2018 01:29 PM)Eddie W. Shore Wrote: [ -> ] (02-21-2018 09:11 AM)martinot Wrote: [ -> ]I just see that on some current calculators, TI have changed from the old [y^x] button to a [X^□] button (which I think makes more sense on an algebraic calculator, if you think about the order of the arguments).

Good catch, I missed that one, Martinot!

Yes. It looks like TI just used to copy some of the key labels from the HP (RPN) calculators like the [y^x] without too much thinking, and now days has changed to copy the [X^□] keys from Casio calculators (which is more appropriate for an algebraic calculator:

(02-21-2018 01:29 PM)Eddie W. Shore Wrote: [ -> ]Speaking of the TI-36X Pro, what is up with the arithmetic operation keys being silver on silver? That has always bugged me on that model.

Yes, that looks like it would be very difficult to see under less than optimal conditions. Very strange, and probably very bad, choice by TI. They can do better than that (and also does on some other of their models).