[50G] connecting to Linux PC

[Thomas Ritschel]

I have a problem which is puzzling me for quite a while now. Perhaps one of our fellow Linux users has a solution:

Recently I've upgraded my Notebook from Ubuntu 12.04 (kernel 3.8) to 14.04 (kernel 3.16). Now I'm facing the problem that I can't transfer data to my HP50g anymore.

When connecting the HP50g via USB cable the device /dev/ttyUSB0 is created as expected.
Then I set the calculator into Kermit server mode by pressing/holding left shift + cursor right.
On the Notebook I start Kermit (from the ckermit package) using this configuration (.kermrc):

Code:

set modem type direct
set prefixing all
set port /dev/ttyUSB0
set speed 9600
set carrier-watch off
set flow none
set parity none
set block 3

The problem is that none of my commands ("rdir", "get", "put", ...) is executed. Kermit is waiting forever, and there is also no busy indicator showing up on the calculator display.

I repeated the procedure several times. I tried different cables. And I tried several LiveCDs of other Linuxes (CentOS 7.1, Fedora 21, Ubuntu 13.10, Ubuntu 14.10). All unsuccessful. Even the latest Ubuntu 12.04.5 (which has kernel 3.13) doesn't work. The problem is also present on two other (desktop) PCs running Ubuntu 14.04 and OpenSUSE 13.2, respectively.

On the other hand everything works very well when I connect a HP48g via serial cable and a serial-to-USB converter (FTDI based). So, Kermit isn't to blame here.

So far it seems that this may be related to a change in the "usbserial" kernel modules. Until kernel 3.11 there was a "hp4x" module which is now part of the "usb_serial_simple" module. Maybe something is broken since then. But then it should have been working on Ubuntu 13.10 (with kernel 3.11) or CentOS 7 (with kernel 3.10), but it hasn't...

Perhaps someone had the same problem and already found a solution.
Any ideas and suggestions are warmly welcome!

Thomas