Transferring files between HP 41 and PC using serial interface


Is there any software that is compatible with Windows XP that would facilitate transfer of files with a HP 41 over a serial link. It is surprising to me that four accessories (the IL module, the RS232C interface, the Extended I/O module and a serial cable) are required for serial communication. Was there ever an optional module that could be plugged into a HP 41 port that allowed direct connection to the PC's serial port (i.e. it provided the functionality of all the four accessories)?

What would be the transfer rate of such a serial connection?

Is the HP82164 HP-IL to RS232 serial port interface a rather rare or expensive accessory to obtain on eBay?


I've used a little GWBASIC file to run on the PC to take text in from RS-232 and put it in a file, but I've never tried doing anything other than text between the hand-held HP's and the PC.

AFAIK, they never made an HP-41 module that directly interfaced to RS-232 because the required power would be awfully hard on the batteries. What manufacturers of some hand-held terminals have done however is to power the terminal, or at least the line drivers, from power received from the PC via the line receivers. Of course that means you couldn't put two of these together since neither one would be supplying power. The interface could be made to use internal power if the other end wasn't supplying it.

Somewhere I saw an article on how to open up the HP71 and connect some wires in someplace to make an RS-232 link. I don't remember if it was in the book "Control the World with HPIL" or in the CHHU Chronicle. Personally, I'm not about to open up either of my 71's which are in perfect condition to add an interface that I can't imagine would work very well without even any way for the line "driver" to go below ground. Instead I got the FSI164A which has two RS-232 channels and has worked perfectly with both the 41 and the 71. (It does have a bug with even parity, but who uses that?)

The HP-41's HPIL speed is very, very slow compared to that of the 71, at something like 150 bytes per second. Still, it's fast enough for most things you'd do with the 41.

I do remember HPIL boards you could plug into the PC, but I never bought one. I did get "71B-Talk" PC software to connect the 71 via RS-232. It was rather problematic (all from the PC end).

One of the electronics industry trade magazines had an editorial last year declaring RS-232 to be dead. They got so much mail from various companies telling why they still use it and it wouldn't be practical to switch to something else that the magazine had to retract their announcement. I for one hope it never dies. It's a simple workhorse that's much easier to incorporate into things than something like USB is.


Hans Brueggemann wrote a program called "HPILCOM" which works great. He once posted a message with his email address on this site:

I'm fairly certain it requires the extended i/o rom though.

Hopefully you can contact Hans and get a copy from him.




an alternative could be using an HPIL-PC card

in combination with Emu41, at least if your PC has an ISA slot.

The above combination is the easiest-to-use solution,

as it requires no special software on the HP-41 side,

just an HP-IL module.



My MLDL2000 will have USB communication, have a look at the specs posted at



hi nicholas,
maybe HPILCOM can do the trick.
just drop me a line, and i'll be sending you the latest version.

yes, x/io is required because of "INP". however, it should be possible to handle program input via "INA" (XF/M module) and some additional programming on the 41.


p-o-r-k-p-i-e-h-a-t-@-g-m-x-.-n-e-t (remove all minus signs)


In retrospect, the HP 41 series calculators were sold at a time when the majority of the users did not own a desktop or laptop computer so the idea of a cheap method of transferring files to a PC was not relevant. I suppose by the time the PC was common, the HP 41 series was near the end of it's product life and HP was developing the HP 48 series as a replacement so the idea of developing a module for interfacing with a PC would not have made economic sense.

Does the HP82164A RS232C interface use rechargeable batteries as a power source?


The hp82164a uses the typical AC power supply that a lot of the other hp devices use (the 71, 75, 97, thinkjet, 9114a/b, ...). Its worth having one if you like the 41, 71, and 75 because it works with all of them. I've even used it with hyperterm (windows built-in terminal program) to provide an external keyboard/display for my 71b. Plus, like I said, hpilcom written by Hans B. works really nicely for the 41.

You should be able to find one on ebay for ~ $50.00 if you look for a while. The manual is in the mohpc dvd.



And the 82164 _requires_ an AC input. The other interface modules (82163 video, 82165 GPIO, 82169 HPIB) just rectify the power input and feed it to a 7805 regulator to get 5V for the logic chips. Those can (in theory) be used with a DC input. But the 82164 does that _and_ it feeds the input to a little step-up transformer which feeds more rectifiers and regulators to get the +/-12V supply for the RS232 driver chips. You can't, therefore, run an 82164 off a DC input.


> Does the HP82164A RS232C interface use rechargeable
> batteries as a power source?

Andy told about the HP, so I'll tell about the FSI164A. The FSI has a DC-10 jack in the side for 9VDC, the pin being +. I think there was an option for battery power, but I didn't get it. (It also had an option for 8 RS-232 channels, but I only got the standard 2.) Since the input is not AC, it looks like it would be easy enough to connect an external battery pack if you wanted to.


Dear HP41-PC interfacing enthusiasts :-)

A small companie called Handheld Portable Products = HPP produced a special version of the HP82164 RS232-IL interface which is battery powered for mobile applications.

Also CMT produced a very nice device, called IL-RAM-Disk unit, which includes a RS232 interface option. Also this device is battery powered for mobile applications.

Actual the standard Windows solution for interfacing HP41 to PC by using RS232 is the software form Hans Brueggemann. As I know Tony Duell created a software solution for Linux operating system.

Alternatively you can use the HP-IL/PC interface card for interfacing your handheld to PC world. For this some different software solutions exist : LINK PLUS, TRANS41 EMU41 and EMU71. By taking this solutions you are able to interface HP41, HP71 and HP75 handheld computer to PC world.

For parctical work with HP41 I prefer using EMU41, because this powerfully software is an advanced emulator , includes some virtuaL IL-Devices and also acts as HP-IL controller for controlling real IL-Devices.

For EMU41 exist user code software solutions for transfering any tpye of HP41 files (data, programm, ASCII, CCD-Module matrix files and NNN´s = non normalised numbers). Also EMU41 includes up and download of complete HP41 rom images (plug in modules). This is helpfull for creating own rom solutions and for programming new hardware devices like CLONIX or NoVRAM...

Best regards - Christoph Klug


The programs I've written for linux allow you to use the Extended I/O INP and OUTP functions to transfer programs between the HP41 and a PC. I've distributed them as commented C source code, and I'd be happy if somebody wants to try porting them to other OSes.

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