Connect HP 50g (or HP 49g+) to a Linux Box with hptalx

Goal: Getting hptalx to work via USB, exemplified with Arch Linux (2.6.32 x86_64).

Having yaourt installed may simplify the following process, since this wrapper for pacman is able to manage and install packages from AUR.

  1. Install chkermit from AUR
  2. Install hptalx from AUR
  3. Since hptalx segfaults if /usr/bin/kermit does not exist, you need to create a link:
    $ ln -s /usr/bin/chkermit /usr/bin/kermit
  4. Add module to kernel, which provides ttyUSB* device in /dev/
    $ modprobe hp4x
    If you wish to do this automatically at startup (not my recommedation unless you really need it often):
    MOD_AUTOLOAD=”yes” and MODULES=(hp4x)
  5. After plugging in the calculator, find which ttyUSB* is used:
    $ dmesg | tail
  6. To be able to use ttyUSB*, adequate permissions have to be set, for this device is owned by root. Sure enough, you could create a udev rule, but the simpler way is just to add the user to the group uucp:
    $ ls -la /dev/ttyUSB* (-> group is uucp)
    $ gpasswd -a user uucp
  7. Set transfer type on calculator to “Kermit”
    Apps -> I/O-Functions -> Transfer
  8. Start Kermit server on 50g:
    [hold right shift + right directional key]
    You should read: “Awaiting Server Cmd.”
  9. Fire up hptalx. You might need to set up the connection [Ctrl + N] first, then you are ready to connect [Ctrl + B].


  1. Ito

    Thank you very much for posting this!

  2. Mark

    This used to work for me but with my current (fully updated) arch setup (march 2013), hptalx chokes at Getting the Calculator Type…

    aur/ckermit 9.0.302-3
    aur/hptalx 1.3.1a-1

    Is it working for you?

  3. luciano

    If your system use systemd (as default in current archlinux and debian wheeze), hptalx, ckermit, sx and minicom are unable to establish a reliable connection with a HP 50g calculator.

    The ModemManager.service interfere with the communication, so it must be disabled AND stooped:

    a) sudo mv /usr/share/dbus-1/system-services/org.freedesktop.ModemManager1.service /usr/share/dbus-1/system-services/org.freedesktop.ModemManager1.service.disabled

    b) sudo systemctl stop ModemManager.service

    After this two steps the file transfer works as usual with hptalx, minicom, ckermit and sx (xmodem). This changes must be made only one time, it will persist after reboot.

  4. Kermit

    What’s wrong with simply installing Kermit on the Linux box? Does that work, and if so what is the reason for hptalx?

    • C-Kermit is just the communications protocol which serves to interact with your calculator.
      With Hptalx you get GUI to your calculator. There is a flie manager, which lets you transfer files easily. You can also run commands on your calculator via a GUI.

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