Is it me or is the HP 41CX the...


Okay, now for the meat of the subject:

I have the following:

HP 25C
HP 29C
HP 65
HP 67 * 4
HP 91
HP 97
HP 41C
HP 41CX * 2
HP 48G
HP 48G+
HP 71B first edition (metal back)
HP 71B last edition (plastic back)
HP Plotter, HP disc drive 9114B, HP HPIL inkjet,
and other stuff mostley HPIL 71B and 41CX from schooldays.

Here is the question, Of all of the above the 41CX to me, is the best, unrepeated, irreplaceable calculator of them all. Mine is loaded with 2xMemory, Infared printer module, Clonix with CCD, PPC, and NAV. It also comes with the Aviation pack, HPIL printer, Infared printer, 4 working card readers, a wand, plotter module, stat pac.

In the cockpit I use the HP41CX because of the timers, alarms (multiple), 20 years of accumulated programs, the accessories and size. I have experimented at work with the 67(love it), 65(fun but the 67 is great), 71B (super fast but awkward and I am still learning basic) and have come to the conclusion that the office requires the HP 41CX.

It fullfills all required requisites when it comes to my job. The kit includes; program cards including a wall, card reader, infared printer and the calc as described above.

The others with the possible exception of the HP71B (I am a novice with it) do not fit the bill. Even the HP32SII does not have the flexibility of the HP41CX (no printer, limited space)

The 48's comes close and were even used at one time but for sheer calculatorness (sp?) the 41CX is the IT machine for me.

Comments welcome.

Wish it had dot matrix LED alpha numeric, NOW THAT WOULD BE RETRO COOL!!!!!


Edited: 22 June 2008, 4:26 p.m.


Wish it had dot matrix LED alpha numeric,

You're saying that you actually WANT to have to charge batteries overnight every time you've used the calculator for an hour or two?

I was with you up until you sprung that one on us.


14-segment LCD displays seem retro enough for me.

Edited: 22 June 2008, 4:33 p.m.



Comments welcome.

Interesting. Of all my HP calculators, the 41 has about the least appeal to me. I really can't tell why, I just don't like it. Never did.

Wish it had dot matrix LED alpha numeric, NOW THAT WOULD BE RETRO COOL!!!!!

Yes. Maybe I would be able to like the HP41 if it had this kind of display. And a metal housing. And some lead ballast inside to make it feel solid.

Last week, almost exactly 30 years after my first solo in a glider, the jet age finally began for me. It was a decision of less than a second which calculator to take with me on my first flight in the real thing (after 20+ hours in a simulator that comes very close to it): An HP 67. But I didn't need it at all, Mr. Honeywell had provided all the calculation power needed to do the job :-)

A few weeks ago they forced me to take my written long-range examination (without which my national license would not be converted into the JAA-ATPL that I need for my new type rating) and again, I had to choose a calculator to take with me. This time it was a Ti-30 eco, because it needs no batteries and is non-programmable and therefore allowed in the exam. With any RPN calculator, my fear would have been that the examiners, not ever having seen anything like it, might have denied it.

Greetings, Max

Edited: 22 June 2008, 5:27 p.m.


I do love the 41C* for the ability to make it's own eproms, ( e.g. Zengrange, CMT..), but for everyday math, The 17bii is much faster and feels more natural as a 4 banger with TVM functions (wish I had a 42S with organic TVM menu instead!).

The FInance program in the PPC module is excellent, and generally comes close to ideal with the IR printer module, and Dual XMEM but the calculations ARE a little slow for me. That is to say I don't like getting the 'flying goose', or the cryptic rUNNINg that you get with the 12C/15c series.

Eagerly awaiting the 20b -> business with a few trig functions! (too bad the 27S was not RPN!)


I have a 41cx plus Advantage module, ZENROM module (same version that recently went on the eBay for $505!), HPIL/XIO double module, and double extended memory module. I also have a 71B with an extra 160KB of RAM, Math module, Forth/Assembler module, HPIL, and loads of LEX files in RAM.

I have the HPIL-to-IEEE488 interface, the HPIL-to-RS232 interface, two 82161A tape drives, a Thinkjet, and the facilities to go from RS232 to SPI, I2C, parallel, Microwire, 1-Wire, IR, or virtually any interface I want.

I've interfaced both the 41 and the 71 to plenty of pieces of "rack-and-stack" IEEE488 lab test equipment at once. I wrote myself a program for the 71 to do most of the 41's alarm capabilities and more, but my 41 is still my alarm clock, daytimer, and phone directory.

Although the 71 has a lot more power, I still use my 41cx a lot more. I frequently write programs for it of 200 or so bytes, but have not used my 10-page programs for it in many years. A few programs have resided in it continuously for 20 years. The nature of my work has migrated over the years so I don't interface these handhelds to external equipment as much as I used to, but still, none of the calcs without HPIL appeal to me. A friend is trying to get me interested in the 50g plus RS232-to-IEEE488 interface and has loaned me one, but I've just gotten started and have only read the first couple of chapters in the User's Manual and can tell you it's nowhere near as well written as the 41 and 71 manuals. I have not yet downloaded the 887-page User's Guide. He's absolutely delighted with the 50g and thanking me for getting him turned on to HP, and I can see how it really does fit his particular work well; but I still think the 41cx was the peak of HP calc design in many ways.

As for the display, the 41's display and accompanying wider viewing angle, long battery life (a couple of years instead of a couple of hours), and sunlight-readability were very welcome improvements over the TI-58c and 59 I used previously with their LED displays.

Edited: 22 June 2008, 8:06 p.m.



Very impressive list of interfaces I must say! For me personally that is one of the great features of the 41/71 that e.g. the 42 lacks which de facto makes it uninteresting to me despite all its other superiority to the 41. (e.g. loved Egan's article about X10/GPS & HP41!)

Can you let us know more about the IR interface you mentioned? Did it go directly via the IR module or via HP-IL to the RS232 interface to a IR sender -> IR receiver and back? Either way it would be interesting to hear about your interfacing(s)




Can you let us know more about the IR interface you mentioned? Did it go directly via the IR module or via HP-IL to the RS232 interface to a IR sender -> IR receiver and back? Either way it would be interesting to hear about your interfacing(s)
The answer is B, but not directly. When I said I had "the facilities to go from RS232 to SPI, I2C, parallel, Microwire, 1-Wire, IR, or virtually any interface I want," I was referring to a home-made real-time workbench computer I've used for controlling experiments, taking data, programming microcontrollers, emulating new circuits we would put into production, and so on. By going through the RS-232 interface to the workbench computer, I can get nearly anywhere I want to go with it with these other interfaces.

There's an outdated web page on it at . The series of pages covers the 41 and 71 a bit too, although I sent the pictures and text to the webmaster who put it up and somehow some of it was lost. (You'll even see pages that end in the middle of a word.) I initially made the workbench computer 15 years ago, and have slowly improved it over the years. I need to get him new pictures and additional circuits to post. I've been talking about making "the next one" for years, but improvements on this one (which were a much smaller project) have postponed the need for another more-powerful one.

Since I never bought the HPIL parallel interface (and I wish I had), the way to print to a parallel printer from the 41 or 71 is to go through RS-232 to this workbench computer which has a parallel printer port.


Geoff; I once had the opportunity to choose my "desert island" calculator. I did surveying for a Catholic/Lutheran funded charity in the upper Amazon. I used my 41cx, Surveyors CoOp ROM & Extended Memory Modules. One extra rainy day i stayed in the hut, figured out their storage pattern in ExMem and wrote a corner angle program to check for entry errors. The 41 is the hight of technology. It's better than TV, but not better than "jungle TV".

Choosing the 41 was easy. Picking my 10 desert island records, now that was hard.


Geoff Quickfall ...

"In the cockpit I use the HP41CX because.."

If your time's up, why delay the inevitable? :-)

I use the HP41CX because of the timers, alarms (multiple), 20 years of accumulated programs, the accessories and size.

You can do all of this (and more) with the 48GX or the 50g, including running your 20 year library of
accumulated programs.

Check out:

HP-41X (scroll to the bottom for screen shots with emulated printer)

41C to 50g Migration
(the 50g is cheap and abundant)


I too have an HP41CX with CCD, PRINTER, HEPAX + 24 !!! 4K RAM or ROM ( at my own choice ) modules immediately available + 40 different ROM ( 4K or 8K ) modules I can upload whenever I want - and if I ever whished an additionnal 80 4K ROM modules of my own programs - + high speed dual way data link with a PC and my HP41CX runs 3 times faster than a conventional HP41 CX. It could even run up to 6 times faster.

All this residing in just one single handheld which fits perfectly into the HP41 pouch !!

This is a true story,... But you know the story, don't you ???

Best Regards from another B 575/767 Pilot !!! :-))

Antoine M. Couëtte

Edited: 24 June 2008, 5:03 a.m.


Here is my bit.
I found that it takes time and practice to bond with specific model of the calculator. One of the biggest problems I am finding is that having quite a stockpile of them and trying to use them all doesn't help the situation. For example I am sure I would love 42s, but I never take it out with me because I have only one of those. On the other hand having 4 x 35s and 4 x 50g, let's me have them with me everywhere.

There is also something else I just can't put finger on. It is almost as if some models had a "soul" and some don't. For example when I compare the feel of the 50g versus 35s - both being current models - disregarding spec comparison, 35s feels more HP calculator to me. Then again, I would love to have SDHC card slot in 35s.

I would love to see that red LED retro future model as well. I am sure that battery technology has improved since 41c days. And maybe they could put a coat of a solar cell over the calculator and a USB port so calculator could start recharging whenever is connected to USB port or left in the light. And obviously SDHC port, so you could easily put - say 8 Gig extra Ram in it. Then I would leave the 42s style of programming on it but have a some SDK on desktop to allow creation of the new functions.

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