• Date : February 2022
• From : Swiss Micros (Direct)
• Price : £185
• Serial : 01266
• Battery Swap
  • 22/9/22
  • 11/02/25

• approx. error +3.5s/d = +40.5ppm
• Correction factor C from C = 2^20 P /(10^6 + P)
• Approximations :
  • C = 1.04858 P
  • P = 0.953674 C
• Calculated C = -42.47

Put a text file /rtccalib.cfg in root directory of FAT drive with contents:

-42.47

After a period of observation the rate is now over-corrected. Try reducing correction to -37.5 which corresponds to a ppm error of 35.76ppm, or 3.26 s/d.

I'm using the 41Z complex number module by Angel Martin to add a 4-level complex number stack. It's a bit confusing at first to get to grips with, but adds a lot of functionality to the the DM41x.

After a bit of trial and error (this is my first play with a “plug-in module” after all) I discovered the simplest way to make the keyboard function normally, and get easy access when needed to the complex functions, was to assign a USER key (usually the statistics summation key ∑+ to the 41Z module function ∑ZL.

Each press of ∑+ now temporarily modifies all the keys to access specific 41Z functions. The functions available are extensive, through the use of the SHIFT key and by multiple presses of the ∑+ (henceforth referred to as Z) key.

I drew out a diagram to show the various functions available.

Once a selection is made the keyboard switches back to its normal behaviour, so all the usual functionality is available.

Most of these are unlikely to be used often - and it's also possible to make a much narrow selection of 41Z functions and make your own USER assignments, rather than use the ∑ZL keyboard - although this might mean you block access to inbuilt functions you might want - which would mean switching out of USER keyboard mode at times. At the moment the ∑ZL option seems the most versatile.

Many of the 41Z functions available are beyond my pay grade and unlikely to ever find a use, but the Complex Keyboard still makes things much easier to deal with.

For example the two keypresses:

Z 1\x

is much easier than the 7 it would otherwise need to invert a complex number

XEQALPHAZINVALPHA I need to practice finding the right function (the main ones printed on the keyboard as well as the new ones provided by 41Z's ∑ZL keyboard, but my fingers are slowly starting to move in the right direction.

One thing I do notice, though, as that due to the need to press various keys (XEQ, ALPHA, SHIFT etc) it's sometimes possible to make a real mess if you miss a vital key in the middle of entering lots of data & instructions and find your stack totally screwed up, or several lines of program code full of nonsense….

I'm sure it'll all become second nature soon enough.

.

This is another interesting module to add the functionality of the HP16C - the Programmer's Calculator designed to handle calculations in various mathematical bases as used in computer programming and networking : Binary, Octal, Hexadecimal and Decimal. I adds much more value than the rather basic functions in the Advantage Pac module.

After much trial and error I found a combination of HP16C module and Library 4 library that worked correctly. The HP16C module needs the Library 4 module, but I found some problems with different versions. Using the versions contained in the Swiss Micros package had a weird bug - the 16* (multiplication) function simply didn't work. I found a post by Angel Martin on the HP Calculator Forum with a ZIP file containing the 2 modules that worked correctly.

Here is the zip file : hp-16c_rev.1a.zip

I'll make a separate guide to using the main features here DM41X HP16C Module

Hints & Tips

• Firmware : https://technical.swissmicros.com/dm41x/firmware/
• Documentation : User Manual
• Product Page : DM41X

• Arrived new with a speck of dirt behind the glass in front of the LCD.
  • Able to remove by carefully prising the glass from its bezel (it's held in with double-sided tape)

Weird behaviour with its "common factor" display

The factorization error in the deluxe version has been fixed by Angel….

Swiss Micros forum discussion about the issue

• the fixed version 41z_bs_2x2_2_.zip
• My page DM41X 41z Module

• See DM41X Progs

Page Updated : 06/03/25 06:49 GMT