September 3, 2007: Added a review of the Sentry CA756 graphing calculator. Made a minor update to the Durabrand 828 versions page to reflect discovery of newer PCB revision to the Durabrand 828. Also combined the reviews of sub-twenty dollar graphing calculators under their own page.
July 30, 2007: Another twenty dollar graphing calculator, Walgreens' Corner Office ATC-139.
July 23, 2007: Added self-test information for the HP-35S and the HP-18C calculators.
June 15, 2007: Added more information about the different versions of the Durabrand 828 that have been sold.
June 8, 2007: Added a short review of the new Texas Instruments TI-30XS MultiView scientific calculator.
May 20, 2006: A significant update to the Durabrand 828 graphing calculator review. A second version of the Durabrand 828 has been discovered. Check out an account of its discovery and differences.
April 1, 2007: Added self test information for the Calculated Industries Model 3405 Real Estate Master IIIx calculator.
February 24, 2007: Added a picture of a 56-function calculator chip (taken with a friend's microscope) to the sub-five dollar calculator reviews. page. Also made a minor update to the calculator forensics tables. Note: If you sent me calculator forensics data between November 6 and December 11, 2006, would you please resend that data.
November 5, 2006: Numerous references were added to the Calculator Related Patents page, bringing the total number of calculator related patent references to 1089.
October 27, 2006: Updated self-test information for the Casio fx-115W and fx-300W calculators.
October 26, 2006: Added self-test information for the Casio fx-82TL calculator.
September 3, 2006: Added self-test information for the HP-50G. Made several months worth of accumulated updates for the calculator forensics tables. Also made several other minor updates.
July 16, 2006: Added a calculator review of the $20 Durabrand graphing calculator. Also added data for the MM5739 calculator chip.
July 8, 2006: Added a new section to the web site: calculator reviews. Initially, there are two reviews, a review of ten different one-dollar calculators I was able to find for sale a week ago, and a review of two sub-five-dollar scientific calculators I found for sale this past week.
April 2, 2006: Added self-test information for the Radio Shack EC-4040 (a rebranded Casio fx-P401) and Radio Shack EC-5500 (a rebranded Texas Instruments Business Edge) calculators.
December 23, 2005: Added self-test information for Casio fx-115ES, fx-300ES, and fx-991ES calculators.
December 11, 2005: Several months worth of accumulated updates for the calculator forensics tables.
November 27, 2005: Approximately 80 patent references were added to the Calculator Related Patents page, bringing the total number of patent references to 943. A minor update was made to the Frequently Asked Questions page.
August 26, 2005: A major update to the Calculator Related Patents page. This update has been in work for many months. Over 860 calculator related patents are listed. They have been divided into fourteen categories to make digesting them easier.
April 12, 2005: Four months worth of accumulated updates for the calculator forensics tables. A significant update to the links page, with the addition of several collector web sites, along with other changes. Other miscellaneous minor updates.
December 4, 2004: A quick update to add self-test information for the TI-84Plus, and make minor updates to the calculator forensics tables.
December 3, 2004: Numerous updates to the calculator forensics tables. Added self-test information for the Datexx DS-883 Graphing Calculator. Created a Kinpo-manufactured calculator self-test page with links to other self-test pages within this site: Kinpo Calculator Self-Test Function Links. Also made several other minor updates.
June 4, 2004: Numerous updates to the calculator forensics tables.
March 13, 2004: Numerous updates to the calculator forensics tables. Added self-test information for the HP-33S. Also made several other minor updates.
December 25, 2003: I had a hard disk problem that resulted in the loss of emails containing calculator forensics data between October 6 and November 1. If you don't see data you sent, please resend it. Now the updates: Several updates to the calculator forensics tables. A significant update to the links page with the addition of links to approximately fifty Far East calculator manufactures or distributors.
October 5, 2003: Numerous updates to the calculator forensics tables.
September 6, 2003: Added self-test information for the Aurora FN1000, and made numerous updates to the calculator forensics tables.
July 27, 2003: Added chip pin-out information for American Microsystems, Inc., General Instrument Corp., Mitsubishi Electric Corp., and MOS Technology, Inc.. Added self test documentation for the HP-9G and Casio fx-9750G PLUS. And, as usual, numerous updates were made to the calculator forensics tables. Numerous other minor changes were made to various other pages.
June 22, 2003: Added self-test information for the Datexx DS-834, updated the self-test information on the Casio fx-115MS, and made numerous updates to the calculator forensics tables.
June 8, 2003: Yes, it has been a long time since the last update - I've been way too busy. By the way, I had some hard disk problems that resulted in the loss of emails containing calculator forensics data between February 17 and April 2. If you don't see data you sent, please resend it. Around that time period, someone also sent me some calculator chip data consisting of several pages of a scanned data sheet and I can't remember who that was - if that is you, would you please resend it. Now the updates: Numerous updates to the calculator forensics tables. Also, added self test data for the Texas Instruments Voyager 200 and the Sharp EL-506D.
February 16, 2003: Numerous updates to the calculator forensics tables.
January 1, 2003: Numerous updates to the calculator forensics tables, and several updates to the links page.
November 16,2002: Added chip data for seven MOSTEK calculator chips. Updated the Printed Resources page, and the calculator forensics tables.
October 19, 2002: Added self-test information for the TI-83Plus, updates to the calculator forensics tables, and other miscellaneous minor updates.
September 20, 2002: Miscellaneous minor updates, including updates to the calculator forensics tables.
August 30, 2002: Miscellaneous minor updates, including updates to the calculator forensics tables.
August 16, 2002: Added self-test information for the TI Galaxy 9x, and updated the self-test information for the Casio fx-991MS calculator. Added a short discussion on computing the forensics algorithm in radians for calculators and old computers only capable of computing trigonometric functions in radians. Also made numerous updates to the calculator forensics tables.
July 27, 2002: Added self-test information for Casio fx-300MS calculator. Also made numerous updates to the calculator forensics tables.
June 22, 2002: Made a long overdue update to the links page. Added self-test information for Casio fx-6200G calculator. Also made numerous updates to the calculator forensics tables.
May 27, 2002: Added self-test information for Sharp calculators. (Thanks to Steve Brauner for recognizing "stupid calculator tricks" on the web site of William Fock as being the Sharp EL-546L self-test!) Also added data to the calculator forensics tables.
May 12, 2002: This web site is being moved to a new host, courtesy of Viktor Toth. The domain name will remain calcinfo.com. This should eliminate the hassle of having to move this web site every time I change ISPs. If you have links or bookmarks pointing at the forensics data, I have created a subdomain forensics.calcinfo.com Also added data to the calculator forensics tables.
April 28, 2002: Added self-test information for the HP-38G, and Casio fx-991MS as provided by Rolf Viehmann. Also added data to the calculator forensics tables.
March 30, 2002: Numerous updates to the calculator forensics tables, and an update to the hints and tricks discussion describing how I was able to coax a known to exist thirteenth digit of precision out of the Texas Instruments SR-56 and SR-60 calculators.
March 10, 2002: Numerous updates to the calculator forensics tables. Also updated the calculator related patents page with links to a few more interesting patents, including a relatively recent calculator-pen patent.
February 15, 2002: Numerous updates to the calculator forensics tables.
February 1, 2002: Numerous updates to the calculator forensics tables. Added a link to self-test function documention for the TI Galaxy 40, which was discovered and documented by Koen van Driessen.
December 30, 2001: Numerous updates to the calculator forensics tables, including a new discussion on hints and tricks for getting at the undisplayed guard digits used in many scientific calculators. Added two entries for calculator-watch chips to the Toshiba data sheet page.
December 2, 2001: Numerous updates to the calculator forensics tables and the self-test function documentation. Also updated the Frequently Asked Questions page, and the Disclaimer.
September 30, 2001: Updates and corrections to the calculator forensics tables. Also updated calculator related patents page, primarily by pointing patent links to the United States Patent and Trademark Office.
September 15, 2001: Added self-test information for the Casio fx-7400G PLUS, the Casio fx-9700GE, the HP-39G, and the HP-48 series calculators. Also added data to the calculator forensics tables.
August 31, 2001: Updated the Frequently Asked Questions page. Also added data to the calculator forensics tables.
July 29, 2001: Added self-test information for the Casio CFX-9850GB PLUS, the Casio fx-115MS and the Calculated Industries Model 8515 ProjectCalc calculators. Added a new Frequently Asked Questions page. Also added data to the calculator forensics tables.
June 25, 2001: Added data to the calculator forensics tables and made a minor update to the Toshiba data sheet page.
May 20, 2001: Added self-test information for the HP-10BII and TI-80 calculators. Also added data to the calculator forensics tables.
May 14, 2001: Added data to the calculator forensics tables.
March 30, 2001: Added information on the display self-test function of the Casio fx-6300G. Added data to the calculator forensics tables. Virtually every page was updated with "BACK" and "HOME" links to facilitate navigation. Additional non-substantive changes were also made to several pages.
February 17, 2001: Significantly revised and expanded the calculator forensics discussion.
February 12, 2001: Moved website to new ISP.
January 19, 2001: Added data to the calculator forensics tables. I have changed my e-mail address to mwsebastian@calcinfo.com in anticipation of moving to a new ISP. My current ISP, flash.net, which I have been happily using since 1996, was purchased last year by Prodigy. Prodigy is soon planning to impose their Membership Agreement, with terms I find objectionable, upon current flash.net subscribers, necessitating my move to another ISP. Also, please be sure your bookmarks point to http://www.calcinfo.com so you will be able to find this site in the future.
December 28, 2000: Added data to the calculator forensics tables.
December 26, 2000: Added pictures to the Radio Shack EC-4033 self-test discussion.
December 23, 2000: Added additional data for the Texas Instruments TMS0100 series chip family, specifically the TMS0101, TMS0110, and TMS0118.
December 17, 2000: A quick and dirty update: Added self-test documentation for the TI-86. I finally convinced my oldest son to relinquish his TI-86 for this worthwhile effort.
December 13, 2000: Added some data to the calculator forensics tables. Also added self-test data for the Casio fx-65 and Radio Shack EC-4033 calculator.
November 24, 2000: Added some chip set information to the calculator forensics tables. This chip information was taken from calculators in my personal collection which were easy to disassemble and from which the chip numbers were visible without unsoldering anything.
November 18, 2000: Added data for the early Texas Instruments TMS0100 series chip family. Also added the first installment of my calculator forensics project, which seeks to help answer the question of who made the chip sets in the various scientific calculators.
October 27, 2000: Added Joerg Woerner's Datamath Calculator Museum to the links page. And, updated the URLs to Viktor T. Toth's Programmable Calculators page, and Frank Boehm's ELEKTRON page.
September 17, 2000: Added Brent Hilpert's Early Electronic Calculator Technology Reference to the links page. Also made some minor updates to the Printed Resources page. I'm sorry that updates have been few and far between, other activities (i.e. school) have been taking too much time away from my calculator hobby.
July 27, 2000: Added self-test function documentation for the Radio Shack EC-293 calculator. This may not be that exciting, but this calculator is probably the simplest one I have seen with a user accessible seft-test function.
July 23, 2000: Added self-test function documentation for the HP-30S to the HP self-test function documentation page.
July 22, 2000: Updated the TI-81 self-test function documentation to include differences found in three other ROM versions. Cleaned up the choice of law provision in the disclaimer.
June 24, 2000: Added TI-81 self-test function documentation to the Texas Instruments self-test function documentation page, and Casio fx-7700GBUS, Casio OH-7700GB, Casio CFX-9800G, and Casio fx-9700GE to the Casio self-test function documentation page. I have also updated the disclaimer by adding forum and choice of law provisions.
May 21, 2000: Added TI-83 and TI-85 self-test function documentation to the Texas Instruments self-test function documentation page.
May 12, 2000: I've registered the "calcinfo.com" domain name. Please take a moment to update you bookmarks to http://www.calcinfo.com.
April 15, 2000: Added Casio CFX-9850G self-test function documentation to the other entries in the Casio self-test function documentation page. (Yes, I finished my federal income tax return!)
March 26, 2000: Added Casio fx-300W self-test function documentation and made minor clarifications to the other entries in the Casio self-test function documentation page.
March 18, 2000: Added Casio fx-270W self-test function documentation.
March 17, 2000: Added data for the MM5725 and MM57459 chips. I also got rid of the old annoying counter.
March 14, 2000: Added Viktor T. Toth's Programmable Calculators page to the links page.
March 11, 2000: Added Toshiba data sheet links.
February 26, 2000: Added calculator related patents page. This update was delayed because work and school are taking more of my time than expected.
January 31, 2000: Added Texas Instruments self-test function documentation for the TI-36X SOLAR and TI-30Xa SOLAR.
January 30, 2000: Added self-test documentation for the HP-71B.
January 23, 2000: Added Casio self-test function documentation.
January 16, 2000: Added self-test function documentation for some HP calculators.
January 2, 2000: Creation of this site.
