FAQ

• Results from trigonometric functions are always in RAD.

  Is the Complex mode switched on? The Complex mode is indicated by a "C" in the status bar and can be switched off by g CF 8.

• If I rapidly type a sequence of numbers, the entered keyboard number(s) are ignored. For example, if I type 123 quickly, the 2 is missed and I get 13 on the display.

  While a key on the computer keyboard is being pressed, all other key presses are ignored. When you pressed the 2, you were still holding down the 1. This is exactly how the real HP-15C behaves.

• Where can I see the version number of the simulator?

  The serial number follows the rules for serial numbers of HP calculators of that era. The format is YYWWCsssss with the following meaning:

  • YY = Years since 1960
  • WW = Week of the year
  • C  = Country
  • sssss = a unique serial
  
  The calculator serial number 6112G04300 means: Built in 2021 (= 1960 + 61) in the 12^th week in Germany. 4.3.00 is the version number.

• The HP logo and the 15C label on the simulator front are missing

  Be sure to uninstall all versions of the "HP15C Simulator Font". Then install the font file from the latest HP-15C package you have downloaded.

• Do you plan to implement other models of the Voyager series, e.g. the HP-12C?

  I don't own any of the other models and I have no plans to implement them.

• How can I exchange the period (decimal point) and the comma (digit separator)?

  Using the mouse: Right-click the ON button or the area around the display and select "Swap comma and period".
  Using the keyboard: Press Alt–. (period) or Alt–, (comma).

• Where can I get a German user manual for the Simulator or the HP-15C Limited Edition?

  The manual for the HP-15C Limited Edition is only available in English. However, the HP-15C LE is functionally identical to the original HP-15C from the 1980s and the Simulator. Therefore the manuals for the original HP-15C also apply to the LE and the Simulator.
  The HP-15C Owner's Handbooks in Danish, English, German, French and Portuguese are available on the HP Calculator Literature page.

• Why do some keys show a small square instead of the correct label?

  Please refer to the Simulator Help under "Preferences | Fonts | Extended Unicode chars for key faces".

• Do you plan to port the simulator to other operating systems like Android or iOS?

  I do not plan to port it to other platforms. There are several commercial HP-15C emulators are available in the iOS and Android app stores.

  I can also highly recommend RpnCalc. It does not have all the features of the HP-15C, but it is free and more than sufficient for everyday use. I use it on all my Android devices.

• Is there a configuration interface or tool to re-map the keyboard shortcuts?

  There is no such thing. The keyboard shortcuts follow standards, like Ctrl–O to open a program, or are straightforward, like E for e^x or S for SIN. The small number of candidates for remapping does not justify the effort.

• I installed the HP-15C font but the Simulator keeps complaining that the font isn't installed.

  In my experience, this is a problem specific to the KDE desktop environment. This problem has not been reported for other desktop environments.

  The KDE font installer does not always update the font system of the underlying X-Windows system. When this happens, newly installed fonts are available for native KDE (QT) applications, but not for pure X11 applications. You will need to install the font manually.

  The steps to manually install a font depend on the Linux distribution you are using. On many systems, namely Debian-based distributions, it is sufficient to copy the font to the ~/.fonts directory.

  If this does not solve the problem, please see the X.Org page about Fonts in X11R7.7

• On macOS I get the message: "HP-15C.app" cannot be opened because the developer cannot be verified

  The following steps work in 2025. The actual steps may change with future versions of macOS.

  • Go to System Settings

    Click the Apple menu in the top-left corner of your screen.
    Select System Settings (or System Preferences in older versions).
    Navigate to Privacy & Security.

  • Locate the Security Section:

    Scroll down to the Security section.
    If you recently tried to open the app, you should see a message that says, "HP-15C was blocked because it is not from an identified developer."
    Next to this message, there should be an Open Anyway button. Click it.

  • Authenticate and Confirm:

    You may be prompted to enter your administrator password to confirm the action.
    After clicking Open Anyway, you'll see a dialog asking if you're sure you want to open the app. Click Open to proceed.

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