SwissMicros DM15L RPN Calculator – HP 15C Inspired |Titanium Shell | Complex Numbers & Matrix | USB | Root-Solver

I like the DM15L as much as my HP11C. Faster and 40 years newer. Swiss Micros is about the only game in town for new RPN calculators. I collect them, I use them. I use the DM15L in my living room with the big TV while surfing the web. Handy for those quick calculations that don't require any programming. I always liked the Voyager (Landscape design). Screen is very readable. Buttons are fine. I also bought the DM15 credit card sized version which is a great novelty, but the buttons are too stiff to use as a daily driver. Cheerleading for Swiss Micros below: My HP41CV has broken posts, bad z-strips, and battery terminals. With manipulation, I can sometimes even get it to power on. My HP41CX is still in great condition except for the battery terminals. It faithfully powers on, but I know it will probably quit before I do. I got the DM41X masterpiece to replace those two. The DM41X improves on the HP41CX with many conveniences like the custom menu and USB interface that simply make the DM41X my daily driver on my desk. The custom menu supplants the plastic overlays from the 41's that let us repurpose seldom-used keys. The DM41X claims to support overlays, but didn't come with any, and my attempts to use a Cricut to create overlays for the DM41X have been promising, but ultimately disappointing largely due to the thin, flimsy overlay requirements. The old 41 overlays were at least three times thicker than what can be used on the DM41X/DM42. I have the HP 49 and the HP Prime (which will likely be my last HP), but my glory days were with the 11 and the 41 series. Swiss Micros understands that bond and has excelled in feeding my passion for these classic calculators.

Excellent re-make of the HP workhorse! I have been searching for years for an HP-15c calculator. All I could ever find for decent prices were used HP-11s units, which, while nice, are financial in nature and not really useful for my own engineering work. I love the landscape layout and RPN entry system. Once you learn and become used to this layout and entry method, "regular" calculators seem painfully clunky. SwissMicros makes these "clones", using the original HP microcode. This means they give the same results, and have generally the same 'quirks' that the original HP models exhibited. But with larger memory storage, 4x the speed, sturdy metal cases and wonderful clicky keys. They're firmware upgradable, include a real-time clock, user selectable operating speed (12Mhz or 48Mhz), three display fonts for your viewing pleasure and long battery life off a single CR2032 coin cell. Perhaps not the decades we got from the LR44/357's in the original HP models, but certainly many months or years depending on your usage patterns. Easy to replace when needed with four screws. Nice heft to the unit, feels very nice in your hands. The keys are clicky, giving very good tactile feedback on button presses, with a solid feel to the whole thing overall. Am I pleased with my purchase? YES, very pleased. Would I purchase again? OH YES! I actually have this unit on my desk, and a smaller version (the DM-15 credit-card sized) in my purse. Don't leave home without one!

I purchased the Swissmicro DM15L, and the calculator was great at first, a good equivalent to the HP 15C. I have an HP that is over 20 years old and works with no problems. The DM15L display is going out; there are several dead pixels spot; at first, no big deal, now it is interfering with the actual number display. Since it is still under warranty, I reached out to Swissmicro support with no response; I emailed them again a month later and included several other Swissmicro employees, and still no response. Now the calculator is useless! I have given the rating purely based on customer service or their lack of customer support and would not recommend their product due to lack of customer support.

I like everything about this calculator except for the feel of the keys. I've been using the original HP15C since 1985 and also bought the limited edition version. I wanted another one to keep at work so I bought this one. The keys on the HP version have a great feel and doesn't need much press force. This calculator needs more force to push the keys which gives it a clunky feel and it takes some time getting use to. Also I found that if you press the keys too fast, the numbers won't register which leads to mistakes in my calculations. I have to slow down and recheck everything I do. I'm at least glad that somebody reproduced this model.

These days there is not much need for a calculator these days more powerful than this. For more sophisticated work I could fire up Mathematica or write in Fortran, or R. However, a scientific calculator from time to time is handy, and this one is a recreation of one of the very best, emulating the HP-15c using the original ROM code. There is no need to liberally use parentheses to get around wrong operator precedence (looking at you, Excel); because in RPN there are no parentheses. The firmware of the DM15L has a little more memory available for data and code than the HP-15c. Externally it is like the original except for a micro-USB port which could be used to update the firmware. It does not take power from that port. Battery access is different; and beware that a violent drop might knock the battery loose. Its keystrokes are little stiffer and a little shorter than on my HP48G, but distinctly positive, and much better than typical rubber dome keys of other brands. The keys are painted. Alas, the days of double-shot injection molded keys are long gone. It is too early for me to tell about battery life, although you can set the CPU speed at either 12 or 48 MHz which I imagine would not have the same battery lives. At 12 MHz it is still faster than the original. The backside, like original, has the “micro-manual”. The contrast of the printing could be improved. The nice thing about the clone is the HP-15c manuals apply, and are freely available. The Advanced Functions Handbook is an education in itself. Because it uses the original HP ROM code, the numerical methods used by the machine remain outstanding. There are no bugs that I can find; typing in examples from the manuals produces matching results in all cases I have tried. The handiest (for me) feature this calculator has is linear regression; so easy to use, so easy to undo mistakes, just right for making calibration curves for [in my case] chemical lab equipment. Need to solve a system of linear equations? No problem (if more than 3x3 typing is tedious enough to want to use something else). Numerical integration? Robust. Root solver? Robust. Complex numbers? Yes. In short, it does anything you’d need out of scientific calculator [not out of a computer] and does it well. It’s handy. If HP wanted to issue the HP-15c for the third time, they could do worse than to go to Swiss Micros to make a production run. 5 stars.

Ok so some of you probably know a weirdo like me who collects calculators. I know I'm not normal, I long y calculators. I don't even really use them for work but I never got over how useful they were. Anyway growing up I used my Dad's HP 11C which my brother ultimately lost. So about a decade ago I went and bought my own used HP 15 C and one for Dad as it was superior to the 11C. I loved it. But the calculator was showing it's age. I used my Dad's 11 C in calculus in highschool and ultimately upgraded to a Ti 89, and an HP 48 G series. One thing I loved about the HPs was RPN. Anyway I deployed to Iraq and while overseas I missed the opportunity to buy the HP 15 C limited edition. These days you can buy them but because of how few are out there you need to purchase a second hand item at prices upward of $1000. When I discovered the Swiss Micro DM 15L I couldn't pass it up. It arrived in a timely manner, especially considering it shipped from Europe. But more importantly this machine rocks. I don't have a 15C limited to test it against, but it certainly is faster than my older model. This calculator uses the exact same voyager layout as the 15C, the feet are sturdier, has a USB port, uses RPN, and is without a doubt my new favorite calculator. If you know someone who collects calculators this is definitely one to give them. I absolutely love everything about it. The keys, the machine work that went into the casing. This calculator is great.

If you are a fan of HP RPN calculators, and cannot justify $500 for a 20-30 year old used calculator, SwissMicros has the calculator for you. If you don't know what RPN is, this is probably not for you. I have used HP calculators since the late 80's. My first was a 32S, but I was always envious of some of the higher models. I have toyed with 28's, 42's and 48's. I have always preferred RPN, but due to limitations of my job, RPN was not a viable option. Recently I changed companies, and we had 12C Platinum's readily available. Not really the perfect calculator for scientific purposes of a power plant, but it was the only RPN calculator that the company could purchase at the store. Wanting a bit more, but not willing to risk my 32S in a power plant, I wanted a bit more calculator, but was unwilling to spend several hundred for one. This was the perfect calculator for what I wanted. Much cheaper than a HP, much more powerful than a 12C Platinum that my company provides me. The keys are not the same as an original HP, and lack the beveled front edge that I have grown to love, but they click very similarly and I feel that I will get used to them quickly. Though I think I would still like to have that bevel. The screen font is made of pixels and not seven segment display, so while not the same as the original, this could be considered as an improvement. Pros- Same physical size, fits flawlessly in a premium HP Voyager leather case, all of your 15C programs run (faster), comes with leather(?) sleeve, much cheaper than a museum piece from HP. Reasonably fast shipping, 5 business days from Switzerland to my home in the US. Adds Real Time Clock features to the 15C. Runs 15C ROM in emulation. Rugged construction. Not the same as HP's Voyager series. The back is a metal tray much more rugged than an original Voyager. The front metal bezel around the screen is much thicker metal than an original Voyager. When you pick this up, you know it is not a flimsy plastic calculator. Cons- Flaw on LCD screen. I attached a picture. This did not affect the function of the calculator, but it did make it harder to read, making a 0 look like a Q. I went to SwissMicros web site and found an email address and emailed Michael directly. Within a day, I had a response that a screen would be shipped to me. A little over a week later, I had a replacement LCD and a simple 15 minute repair later the flaw was gone. Lack of manual. Not really the problem of SwissMicros, but a limitation of this unique situation. Swissmicros may be able to construct this recreation of the original, but they cannot provide HP's copyrighted material. A little digging on the web and I had a PDF of the original 15C manual. In box there was no manual on how to make adjustments to the emulator that runs the calculator ROM. The instructions you need are readily available on the manufacturers web site. Minor issues with broken links on the SwissMicros website. Links to updated ROMs don't work right, but viewing all files allowed me to get to the updated files I needed.

I got this as an upgrade for my old HP-11C and I am very impressed with the quality you get for the price. The keys have a very positive feel and the display can be adjusted for contrast. You can even change the font. It functions blazing fast and reproduces all the functions of the original HP-15C. When it arrived, the display had some pixels that wouldn't turn off, but I followed a simple procedure that Michael from Swiss Micros emailed me and now it's fine. For quality and customer service I give it 5 stars.