As Lubuntu user I knew it would be no small feat to connect my computer to my HP50G, HP39GS and HP39GII via USB. The Linux Wine emulator won't map the PC's USB port as a phony COM1, despite my best efforts, though somebody out there may have succeeded at this task. This rules out using the software shipped with the calculators, or even Windows Hyperterminal, for file transfers.
However, the wonderful DOSBox emulator for Linux works quite well.
The key is the addition of this line to its configuration file:
serial1= directserial realport:ttyUSB0 rxdelay:60
As long as the calculator is USB attached and switched on, the "ttyUSB0" device pops up in Lubuntu's /dev folder. This is mapped to COM1 by DOSBox (DOSBox needs to have been launched from a terminal window with the "sudo" prefix and administrator password input or it won't be allowed to acquire control of the USB port).
I have had mixed success using the venerable Qmodem Pro terminal software for MSDOS with this arrangement. I can Kermit files to and from the HP50G. I have pulled files off the HP39GS via the Xmodem protocol but I have not managed to push anything across to it. The data will transfer but the HP39GS crashes out at the end without laying the files down to local storage.
The HP39GII puts up the strongest resistance. On connection, its USB port appears as /dev/usb/hidddev0 and won't map as a serial tty type of device (HID class USB ports won't do this, I think).
Of course, the HP39GII emulator runs nicely under Wine but sans USB.
Its along time since I blew 15 hours hacking comms software around trying to make reluctant devices talk to each other. It leaves you kind of giddy!
Edited: 9 Aug 2012, 3:11 p.m.