HP 41G


Could someone tell me if the "HP 41G" exists or not?

A potencial seller is offering one "HP 41G" but I never heard of it.

The only reference I found on the www is http://www.ohiopeps.org/calculators2.html.

Thanks in advance.




I think he or she simply mixed up descriptions,
as you can see for the HP-48.



Obviously a "typo" and should read 41C, not 41G.


So we know that the seller doesn't know how to use the calculator. I wonder if it's good or bad.


Thank you all. You confirm what I thought.

But I send him this question:

Spanish: "Podrías revisar el modelo, ya que segun entiendo la HP 41G no existe. Gracias.".

Translation: "Could you check the model name, because as far as I know the model HP 41G does not exists. Thanks.".

And his answer was:

Spanish: "hola, revisado, nada para modificar, salu2".

Translation: "Hello, checked, nothing to update, regards."

Now I asking him for a photo...


Hello my 41C/CV/CX Gurus,

Recently this question is coming to my mind more often than before. I'm good at 41C programming. Back in 1983, I used my 41CV for writing engineering/scientific applications programs due to lack of PC's existence and inaccessibility of mainframes (turnaround time was half a day). Some of those programs are still in magnetic cards. Now I have 6 PCs, but I still love my CV, simply because PC has advantages and disadvantages, so does the CV. Solving a very complicated math with a fewer variables still outweigh the CV over any PC or mainfram even today.

Since I made my case, here is the question. Is there any interface available for 41CV that I can download my programs to PC? If there is, it will open a door for me. I can write new programs in PC domain (utilizing convenience of fullsize keyboard), edit it, and then upload it to CV. If program works, I can delete that from CV to free up memory while I can save the code in the PC hard drive.

You may wonder why am I so concerned when I have a card reader. My friends, I have a bad news. My card reader was spitting goo recently. I tried to fix it per instruction that available in this museum web site, but the card reader is giving malfunction message now. I guess I toasted it. I have either to buy another card reader or borrow one to read off these programs.

Hope, some of my learned friends here can rescue me by providing answer to my original question; or feel free to provide me practical solution perhaps exist today which I may not be aware of. I'll remain open minded to all of your suggestions,and I'll read all of your feedback. Thanks,


Edited: 27 June 2003, 11:57 p.m.



You are a frequent visitor to this board. Can you take a whack at it to my original post?

Why no one is reponding to my question, I would never know. Is it something I said?




I don't know whether you intentionally ignoring me. If you are not, would you please try to respond to my question under the heading "HP 41C/CV to PC Interface Question" message?



HPIL is the only interface made for the 41C, it requires an HPIL Module (82160A) that plugs into a 41 port, and there is also an HPIL card for the PC - HP used to make one (82973A) that you might be able to find on Ebay or in the Museum Classified ads, also Christoph Klug in Germany has designed his own PC HPIL interface board and you can buy one from him. Then you can run an HP41 emulator from Jean-Francois Garnier in France on the PC to write and run HP41 programs on the PC and move them between the PC and a real 41 via HPIL. Here is a link to an earlier thread where Christoph answered the same basic question:




Thank you for your reply. I have read your response as well as all other Q&A through your link. Amazing how much effort went so early on just to do that what I'm looking for today. It appears to me that the solution is not that trivial as I would like it to be, nonetheless, there is a solution exists. But it may not be practical, due to discontinued product lines. Bits and pieces may be available through auction sites, but there is no guarantee of their working order.

I have not been kept up with the HP-IL side at all, thus this old question has surfaced as new by me, which is the clear evidence of my ignorance.

In conclusion, I see no solution to my problem with reasonable expense and effort. Despite this gloom ending to my expectation, I still hope, someone (hardware nut and 41C lover) will come up with USB cable type solution so that Windows XP can be interfaced with 41C.

Please, keep me in the loop, if it is not too much to ask. I think you, Luiz, and two other guys (I don't remember the names off hand) are most knowledgeable and visible on this board.

Thanks again,



I don't think the HP41 HPIL module is that hard to find, and Christoph's board costs $150, I think - not cheap but not outrageous. You might try downloading the free version of the emulator and see how you like it, I understand it does just about everything except the HPIL communication. You could move some of your programs by hand just to try the system out.

You could also get the PPC (or maybe the HPCC?) CD-ROMs from Jake schwartz and look for an article about something called the "bender coupler" - it was an idea that used the beeper in the 41 as an output device. I think I've also seen articles about using the bar code wand, modified, as a general purpose input device (might have been the timer module). And if I'm not mistaken, you can print bar codes on your PC with the emulator, so you could develop your programs on the PC and print out bar codes to load them into the 41. Somebody with a working card reader and HPIL system could read your cards and put them on disk for you.

Also, I wanted to add to my earlier message that there are other PC programs besides the emulator that can be used to transfer information on HPIL with the PC HPIL card. There is the software that originally came with the 82973A card from HP and another product called LinkPlus, they make the PC look like an HPIL disk drive and printer to the 41 (or 71 or 75) - LinkPlus apparently does it much better than the HP software. But the emulator only costs $20 or $25 for the registered version that works with HPIL - I think that is a bargain! I've downloaded the trial version and I am trying to get an older PC set up to run it on - you need an ISA slot for the HPIL card - but I haven't actually used it yet.



Thanks again. Since you have provided wealth of info on this, would it be too much to ask to review the summary that I laid out in terms of plan of actions?

Plan A: HP-IL Module (82160A), HP-IL PC Card (82973A), HP41 Emulator software (third party).

Plan B: HP-IL Module (82160A), HP-IL PC Board (Christoff Klug), HP41 Emulator software (Jean-Francois Garnier).

Plan C: HP-IL Module (82160A), HP-IL PC Card (82973A), LinkPlus hardware (third party),and driver program (HP).

Plan D: Bar code solution direction (which I'm not clear on the flow......?)

Plan E: HP-IL Module (82160A), HP-IL Extended-I/O module (82183A), HP-IL RS232C (82164A) interface, and Tony Duell's lifutils for Linux.

Plan F: MLDL2000 (Meindert Kuipers). No details are known yet for other parts involved in this solution path. But this solution will lead to use USB cable connection (modern day solution) as per designer's promise.

Can you perhaps fill up the gaps for the accuracy on the hardware and software needed, if I have missed to capture from your response?


Edited: 29 June 2003, 8:26 p.m. after one or more responses were posted


Plan E: HP-IL Module (82160A), EXT-I/O module, IL-RS232C (82164A) interface.

With this setup I use Tony Duell's lifutils for Linux.

Works great with my 41 & 71.




Now we have a good compilation of various choices. Thanks for you to stepped in. I hope, Ellis will be kind to fill up the Plan D, and add more choices if he has any left in his bag.

In the mean time, can you perhaps, provide me HP part number for the EXT-I/O Module?

Are EXT-I/O Module and HP-IL RS-232 (82164A) two separate parts?


Edited: 29 June 2003, 12:19 a.m.


Yes, the Extended I/O module is a separate product HP did, which adds a lot of control to the HP-IL which you don't have otherwise.

The Extended I/O is HP82183A.


Plan F: use my MLDL2000.

Expansion to this will likely offer USB. This is not an end-user level solution, but those who like hardware and M-code programming will be able to come up with a working solution.

Just wait a few more weeks for all the gory details ;)




I'm intrigued by your solution. Would you be able to elaborate your solution ahead of two weeks that you are referring to? Let me pose some questions for you.

1) Do I NOT need HP-IL module 82160A any more?

2) I presume your device is connected to the PC by USB cable, right?

3) Then what kind of cable do I need to connect your device to 41CV?

4) Will there be another adapter from calculator to your device?

5) Or, maybe HP 82160A still needed, but also needs a HP-IL standard cable 82167B to connect your device?

6) Still perhaps a driver program is needed to run not only your device also to communicate with the 41CV, right?

Please respond at your earliest possible time. Thanks.



I am busy trying to get my hardware to run and working on finalizing the specifications, that is why I asked you to wait just a few more weeks. Go and download the preliminary specs at www.kuipers.to/hp41 and follow some of the threads on this forum, Searching for my name and/or MLDL will probably get you enough useful threads.

Note that my hardware is not ready for production. I will NOT be able to offer a full working HP41 to USB solution. As my MLDL2000 is still in development there is not much specificics that I can give you. Not that I do not want to, but because I simply do not know, especially about the USB connection. Beware that I will not be able to supply a complete nicely wrapped product, but rather PCB's with programmed components. It is up to the user (you in this case) to somehow plug it into an HP41 (for example by using an old cardreader housing) and provide all the cables.

If you want a working solution now, go get Christoph Klug's nice piece of HP-IL hardware!



Plan A and Plan B are functionally identical. Jean-Francois's emulator and either Christoph's or HP's PC HPIL card. As Christoph points out in a later post, no HP41 Extended I/O module is needed. On Plan C, LinkPlus is a program that runs on the PC. It should work with either the HP PC HPIL card or Christoph's. The HP software I mentioned is an alternative to LinkPlus (with lesser features, I think) - this software came with the HP card and should be easy to find. Plan D is a one-way solution: use an emulator on your PC to develop HP41 programs and print them out as bar code on your PC's printer (I understand some HP41 emulators will do this but I'm not sure which ones, if any.) Then you can load the programs into your HP41 with the bar code wand (82153A).



Here's another option....

HP-IL Module (82160A)

9114 Disk Drive

Leo Duran's User Code Tools

LIFUTIL or LIF software

Also, check out the MoHPC
FTP Page

If you are linux-enabled, Tony Duell has written some excellent tools, as mentioned by Chris.

Edited: 30 June 2003, 12:11 p.m.


As for Plan D : It's strictly one way (from the PC to the HP41), but you don't need an HPIL module in the HP41. What you need is an HP82153 wand.
You crack open the wand module, and solder an opto-isolator chip inside (the wand remains fully functional, and can still read barcode). You then link the opto-isolator to a little interface circuit which connects to the PC.
The PC sends out bytes that correspond to HP41 barcode, and the interface turns them into long and short pulses to the optoisolator. The HP41 + wand module then 'thinks' you're scanning barcode, and, for example, loads a program.
The scheamtic of the interface, source and hex files for the microcontroller, details of modifying the wand, and linux-based driver software are hidden in my LIF Utilities for Linux distribution.
The interface as given connects to a normal parallel printer port.
Personally, if you have the choics between buying a wand and buying an HPIL set-up, go for HPIL -- it's a lot more versatile. But if you already have a wand, and don't mind doing some soldering, it's probably worth making the interface.


Hey, John;

I'm completely sorry... Actually, I did not read your posts till now. I'm doing something: I'm avoiding to go into themes I have low level of knowledge about.

There is one of our brainy contributors that posted good stuff about this subject a couple of weeks ago. I cannot remember his name, sorry, but it's not gonna be hard to find him. If I'm not wrong, he developed his own version for a daugtherboard that allows the HP41 to communicate directly with a PC.

I'm completely sorry, I'd really like to help. I wish I have the knowledge and the way to assist you doing this. I read the titles and did not even open the posts...

Can you forgive me?

Luiz C. Vieira - Brazil

P.S. - I mean the knowledge to connect the HP41 directly to a PC, as you mentioned in your first post; what I kow for sure is that it involves extra, and in some cases too expensive, hardware. I see Ellis has given good and necessary directions: the name of the man is Christoff Klug, as mentioned. Success!

Edited: 29 June 2003, 1:19 a.m.


Dear HP41 enthusiasts,

here I am :-)

Interfacing HP41 to PC is absolutely nice and powerful for today HP41 user !!!

Take the low priced IL-Module from ebay and the original HP82973 PC interface card or the 100% hardwarecompatible replacement solution from me. The price for this (150$) is absolutely fair, because you are not able to create a own hardware solution by yourself, including IL-terminal, IL-transformer and IL-chip, electronic components and a professional designed pcb. This project is only possible by the input of some HP41 enthusiasts from Germany, France, Great-Britain and USA...

You need not the EXT-I/O module, because typically ebay price for this is placed in in the range of 100$...200$.

For software take the absolute fantastic EMU41 from Jean-Francois Garnier (France) : Only this gives you maximal features including HP41CX emulator, plus the complete range of virtual plug in modules including advanced modules like CCD, PPC, Paname, EXT-IL, SkwidInk. Furthermore EMU41 includes advanced RAM-box features and real HP-IL support : You get some virtual IL devicels like printer and mass storage - and you are able to interface your real IL devices (for example a IL-plotter or the HP3468 multimeter)to EMU41. And your real HP41 ;-)

Working with EMU41 is identic to operating a real HP41, and installing the HP-IL/PC interface card to a PC motherboard with ISA slot is done in less minutes. Needed PC operating system is DOS or WIN98 or WIN2000/NT/XP....

Best wishes from Germany - Christoph Klug


Hi Christoph,

Thank you for responding. I've been getting vote of confidence for your products as one of the reliable solution path.

I have a few questions for you. My understanding of hardware requirements for your solution path are:

1. HP-IL module (82160A) ...procurement source: ebay

2. HP-IL PC Board (Christoph Klug).direct purchase, US$150

Software requirement:

3. EMU41 (by JFG)..Procurement source: unknown; cost:US$?

4. Is my understanding correct? If yes, can you please provide answer to item 3? If my understanding is incorrect, could you please revise it?

5. Where does your board get installed? Is it an external device, or ISA card, or PCI card? Do you have any top level schematics on integration of 41CV, your device, and computer?

6. Will your device work with Pentium-4 PC?

7. Will EMU41 work with Windows-XP? Is GUI DOS? or Windows?

My sincere hope is that you would be kind to take time and answer my questions. Once I understand the top level loop and successfully identify all required parts, I'll start my procurement phase. Thanks,


Edited: 30 June 2003, 4:35 p.m.


Dear John, dear HP41 enthusiasts :

nice discussion about HP41-PC Interfacing. Some different solutions exist, and may be we get some more in future ? Now I want to give you more details about the "HP41-PC gateway & emulator" which is based on EMU41 from Jean-Francois Garnier :

PC-hardware :
Unfortunately the former software solution Link Plus is limited to slow PCs like 286/16MHz machines. Software Trans41 is compatible to modern machines, also EMU41. I tested both software solutions with some different PC hardware from 286/16MHz up to fast 1GHZ Athlon machines. You need a motherboard with ISA slot, actual no solution for PCI or USB bus exist. Also today ISA is an industry standard for PC applications and some special and exotic ISA cards exist beside modern PCI systems. If you need an old ISA slot PC, may be you find one in the garage of your neighbour ?

PC-operating system :
EMU41 (and Trans41) run with DOS, WIN95 and WIN98SE. For this installation is absolutely easy. For modern operating systems like WIN2000/XP/NT you need an additional address routing software tool (tested from Leo Duran). A text help file which describes installation procedure and first steps is available from me.

Needed equipment :
You need your HP41 with HP82160 IL-Module. The non exotic IL module you get from ebay. Price is placed in the range from 20$ up to 60$. Furthermore you need the HP82973 HP-IL/PC Interface Card – or the replacement unit from me. Price for the last is 150$ plus transfer costs. You also get some documentation and nice software tools. From Jean-France Garnier you get the personally signed full version of EMU41 for a fee of 20$. This includes HP-IL features. The basic EMU41 you download free from Jean-Francois Garnier´s webpage...

Human Machine Interface of EMU41 :
Like the real HP41 also EMU41 includes a basic HMI : You get a DOS like screen display and use the PC keyboard. No mouse assistance. No photo realistic graphic design. But compatible to the great range of PCs.

HP41 – PC :
EMU41 offers you some different solutions for transfer of data, programms and files between HP-41 handheld and PC :
1. HP-IL (bi-directional) working with virtual mass storage unit
2. HP9114 IL-Disk Drive (bi-directional) Only possible for old floppy drives/PCs like 286
3. HP82161 IL-Cass Drive (bi-directional)
4. Barcode plot with EMU41 and virtual SkwidInk module (only download to HP41)
5. Under development. Actual Jean-Francois Garnier works on it...

Some more information about EMU41 and HP41 software solutions you find on the web page of Jean-Francois Garnier http://membres.lycos.fr/jeffcalc

Best wishes from Germany – Christoph Klug

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