Posters for Sale
Other Great Posters
Frequently Asked Questions
HP-42S for the PC
Calc98 for the PC
The Curta Poster
Curt Herzstark Interview
Curta: Dimensions & Timing
Curta Repair Manuals
Jack's Curta Repair (US)
Hans' Curta Repair (Europe)
Romano's Curta Repair (Italy)
Curta: The Ayen Collection
Curta: Ray Traced
Curta: Cut & Special
Curta Backup Article
Curta Museums & School
Inside a HP-11
About a HP-95
Made in USA
30 Series Derivations
Welcome to The Calculator Reference
Here you will find a wealth of data I have collected over the years on general calculators, HPs calculators,
TIs calculators, and on my all time favorite mechanical calculator, the CURTA.
I recent years I have become an expert with the amazing Curta calculator. And it's mechanical not electronic!
But it represents a final ultimate, state-of-the-art achievement in the mechanical world before the electronic
calculator revolution took over and over night obsoleted all mechanical machines. Interestingly the Curta held
on for many years because it was so popular among road rallyest and surveyors.
I do collect and study the manufacturing variations of the two models of the Curta calculator. My two exploded view Curta
posters are wildly popular around the world and have been featured in museum displays and displayed in the halls and offices of NASA.
My favorite electronic calculators are HPs but I don't plan on this page even starting
to compete with "The Museum"! HP introduced the
1st scientific calculator (HP-35) then introduced the first business calculator (HP-80).
To this day the all time most popular calculator is the HP-12 Business calculator. I still
like to gripe about why HP abandoned the scientific calculator (HP-11, HP-15) in this wonderfully convenient format.
My Calculators of HP poster is another popular poster I created. It even serves as a reference in the support offices of HP.
Finally my newest posters of the History of the Telephone and
Modern US Currency are the latest additions to my poster line up.
Yes, a slight deviation from calculators but I always remembered touring the phone company as a child and receiving a poster
that showed the history of the telephone. My Telephone poster is an updated tribute to this now 45 year old poster.
I also find the art and design that is in the US currency amazing. My Modern US Currency poster
arranges all the major version of all the denominations.
Showing both the front and back side of each bill so you can study and appreciate the art and changes that have happened to
the US currency over the past 100 years or so. I also hope this poster can serve as a teaching aid for school teachers.
Look around, enjoy yourself, and marvel over how calculators (both steel and silicon) have changed our world.
NOW SIX POSTERS ARE FOR SALE!!!
The Calculator Reference is proud to now offer SIX fabulous posters. The wildly popular
Curta Calculator poster, the Curta German poster, the Calculators of HP poster (version 2), The Telephone Story, Modern US Currency, and Morse Code.
Click on any picture to learn more.... -Rick-
OTHER GREAT POSTERS
(Click On A Poster)
Here are links to some of my favorite posters that other people have created. Click on a poster to learn more.
Here's an article that was in the newspaper about my calculator collection. In the photo the newspaper photographer
wanted me to be surrounded by some of my calculators. So we arranged a ping-pong table in the background and a card
table in the foreground. Then we placed two wide boards on either side so there was a small hole in the center. Next
we placed all the calculators we could fit on the tables and then I squoze into the center for the photo shoot.
It made for a cool shot but sadly the photographer would not give me the original.
Learn more about the HP-12C Platinum, HP-32C, and the HP-33CS on the HP Reference page
Here are places that will help you with your most frequently asked questions
concerning repairs, spare parts, and manuals.
Frequently Asked Questions
Calculator Collectors, Data, Classifieds, Mail Distribution Lists, and Forums
The title says it all, this is a collection of Collector Lists, Data Lists,
Classified Lists, Mail Distribution Lists, and Forums.
If you are wanting to buy or sell a calculator then reference the Classified
Lists, Mail Distribution Lists, and Forums section.
Free 42 (HP-42S for your PC)
Free42 is a re-implementation of the HP-42S Scientific Programmable Calculator and HP-82240 Printer.
It is a complete rewrite, not using any HP code. It does not require an HP-42S ROM image.
Even though it contains significant enhancements compared to the original calculator, Free42 remains fully compatible with the HP-42S, both in its user interface and in its ability to run programs written for the HP-42S.
Free42 is an Open Source project. The executables and source code are released under the terms of the GNU General Public License, version 2.
Over a million PC users have already downloaded Calc98, our popular free engineering,
scientific and financial calculator for Windows. The calculator includes functions for
statistics, use of different number bases (binary, octal, hexadecimal and base-n),
metric units conversions and physical properties and constants. It has financial functions
including investment, loan and mortgage calculations. It also calculates time functions
and has a stopwatch feature and RPN (Reverse Polish Notation). It runs on Microsoft Windows
(WindowsNT, Windows95/98/ME, Windows2000/XP) and WindowsCE (Pocket PC).
Here is some information on some very interesting and some very common
desktops that I own.
Why is the telephone touch-tone key pad arranged differently from the calculator key pad?
Why is the keypad arrangement different for a telephone and a calculator?
Doing the Numbers - Why Calculator and Phone Number Layouts Differ
This is my article on Electronic Displays that appeared in the Winter-Spring
1997 International Calculator
The Calculating Machines Numbers
If you've ever been to Erez Kaplan's
-- Calculating Machines page (now available at the Wayback Machine--thanks Angelica Landicho) then you will have noticed his cool rolling
numbers image. Click this title if you would like to see all of the different
numbers used in this cool image. Go to his page if you want to see the
The Collector's Guide to Pocket Calculators
"This is another must have for ANY calculator collector." - Rick Furr.
"The Collector's Guide to Pocket Calculators"
by Guy Ball and Bruce Flamm is back from the printer and now being shipped.
This 200+ page, softcover book contains a detailed listing of over 1500
known portable/pocket calculators from the early 1970's (the "Golden Age
of Pocket Calculators"), as well as historical information from the 1960's
The book features over 470 photographs of various models from over 220
manufacturers around the world (including calculators from lesser-known
companies in England, Switzerland, Netherlands, Spain, Germany, Bulgaria,
"The Collector's Guide to Pocket Calculators"
also includes a comprehensive value guide to help you gauge rarity and
desirability of the various models -- especially as they relate to each
The book can be purchased for $23.95 plus $4 for USA first class mailing
($6 to Canada and Mexico, $8 for airmail to other countries). California
residents please add $1.86 state sales tax.
P.O. Box 345
Tustin, CA 92781-0345
For additional information, contact Guy Ball
The Calculator Reference by Rick Furr (firstname.lastname@example.org)
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