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I've got a 41cx with 2*x-memory and the advantage pac. My question is which module would you use as the 4th and last port ? I personnaly have a stat pac but I'm sure there's a better pac.
An other question is, according to you, which is the best configuration of a 41cx ( I mean internal extension and not external in order to fit into the leather case) ?

Cyril --

You've already "maxed out" regular and extended memory with your configuation, as well as included the best ROM made by HP. There's not a whole lot of room for improvement, but here are a few ideas:

  • The Math/Stat Pac would provide a few things that the Stat Pac alone and Adv ROM together don't provide -- hyperbolics, Fourier Analysis, and triangle solutions.
    Price: about US$40

  • An Infrared module, along with the 822240B printer will allow the 41 to print to the same printer used by the 42S, 17B/II, 27S, 28C/S, 48S/G, among others. Price: US$100+ for Pac; US$90(?) for printer

  • A Naviagation Pac provides 8 kB of useful programs for navigational calculations and celestial-object locating. Price: US$100+ for Pac

  • Save it for a Card Reader or Wand? Price: US$100

  • A specialty module for advanced programming and other functions: e.g., Hepax, PPC

All above prices are eBay US, not including shipping. I have all three HP modules for my 41CX, but none extra for sale.

-- Karl S.

Here's what I'd put in a CX :
ZenROM, HPIL Development module, HPIL module, card reader.

And in a CV :
Extended Functions, Extended IO, HPIL, card reader

(In fact I have 2 machines configured like that at the moment, along with others that I often change the modules in).

I sure like having the ZENROM in my 41cx. There wouldn't have been any point in my getting the 41 in the first place though if it weren't for the HPIL. I've interfaced it to a lot of workbench equipment, not just the little printer and digital microcassette tape drive.

The Extended IO is nice to have with the HPIL, and I had them put it in the same module with the HPIL so it wouldn't take an extra port. So with HPIL, ExtIO, Advantage, and ZENROM, I have one port left, and I would like to put a double XMEM or an MLDL there.


1) I would put in the CCD module.
2) I would do chirurgy on the 2 X-memory so they will become one module
3) In the one that come free I would leave open so I can plug in any device I need from time to time like the printer, the Wand or cardreader etc.

Hi !

My proposal :

- Advantage Pac
- Double Xm module
- IR Print Module
- Clonix burned with whichever ROM you fancy (Xrom compatible)


- Advantage Pac
- IR Print Module
- NovRAM acting as HEPAX + burned with Sandbox

...and You can sell your Xmem as it becomes useless with the Hepax permanent memory....

Credits and sources :

- both Clonix & NoVram are available through Diego Diaz (Harware and software)

- SandBox is a creation from Angel Martin and is available on the STYSEWENI :
"the Site Thou Shalt Evoque Without Ever Naming It" (Sorry, unfortunately it's not a joke)

- XMem is a kind of joke created by Hp to mimick a filesystem, extend the Hp41 life and increase the stress level generated by MEMORY LOST.

Just my 0.00002 Eurocents

Best regards from Paris


Sorry, I forgot,

In the slot freed by discarding the Xmem stuff, put an HP-IL with a Mass storage (cassette or disk), a Digital multimeter (to test your renewed rechargeable battery pack).

I shifted from batteries to rechargeable after eating out all N-type batteries with the peripherals.

Maybe one day we should try to benchmark the power consumption of all our beloved extensions...

Bonne soirée.