Ask Klaus!

ISDN Box

Question:

I have an Eumex ISDN box, which is supposed to work as both a converter to analog telephones and as an USB ISDN modem for connection with a PC. The box does not seem to be recognized as a modem or network card by kernel 2.6.24; is there a way to add a driver to the kernel to make it work like an ISDN PCI card?

Answer:

There is – or rather, there was – a driver for this box on eumex.sourceforge.net, but it only supports a few variants of this ISDN adaptor, especially the 504 and 604 series with a USB connection.

Worse, the module only works for some kernel versions in the 2.6.9 range, and, because of a changed USB API, it does not compile anymore with 2.6.24 and up.

Even worse: Most of the popular, cheap ISDN adapters you can buy in stores are all no longer supported, not even by proprietary and/or vendor-supplied resources.

The entire ISDN field seems to be a abandoned technology, and for some devices, you won't even find drivers for proprietary operating systems anymore.

For using ISDN with current distributions and kernels, either you need very old ISDN hardware, or you need to check the (very short) list of supported ISDN hardware in the most current kernel, which consists of mostly PCI cards. The easiest option might be to use an ISDN router, which is configured through a web interface and provides Internet access by LAN or WLAN.

Scanner

Question:

After a long battle with Windows (most recently XP), I decided about two weeks ago to change to a Linux operating system. I installed Ubuntu LTS 8.04 (Hardy) and have enjoyed the speed and simplicity of the system. However, one problem remains: Ubuntu (via XSane) will not recognize my scanner. I simply get the message "No devices available." The scanner continues to work fine on the Windows platform, which I have left installed on my computer (an IBM T43 laptop), and the XSane website reports that my scanner, a Canon LiDE 60, works well with Ubuntu 8.04. What can I do? I am a novice on the computer, so please give step-by-step advice.

Answer:

This scanner is well supported, starting from Sane version 1.0.17, so it may just be a problem with permissions for accessing the scanner device. First, make sure you have the sane (which stands for "scanner access now easy") software package installed in a recent version. Also, for some scanners that need firmware, you might need the corresponding sane-extras package.

To check whether your account is in the "scanner" group, please open a shell window and type:

id

which should tell you something like:

uid=26015(knopper) gid=100(users) Gruppen=20(dialout), 21(fax), 22(voice), 24(cdrom), 25(floppy), 26(tape), 27(sudo), 29(audio), 30(dip), 44(video), 46(plugdev), 60(games), 100(users), 106(usb), 118(fuse), 125(netdev), 135(vboxusers)

Of all these groups that my user account belongs to, the scanner group is missing, therefore accessing the scanner device, which usually belongs to that group, won't work for the user knopper.

In this example, to add knopper to the group scanner, you can issue the following command as root:

usermod -a -G scanner knopper

or use your distribution's admin tool for adding your user account to this group. Then log out and back in again for the change to take effect.

The command

sane-find-scanner -v

should now show the scanner, once it is plugged in, and xsane and xscanimage should be working. If the command only shows scanners when issued as root, you still have the wrong permissions for accessing the scanner devices.

Please check /dev/*scanner* for a hint about which group your user needs to be added to in order to get access to the scanner devices.

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