Re: [Nolug] console connection from linux

On Mon, Dec 6, 2010 at 5:09 PM, Petri Laihonen <pietu@weblizards.net> wrote:

> I'm trying to connect to the networking switch via usb to console cable.
> (usb <--> rj45) I have serial to rj45 cable also, but my laptop does not
> have serial connector.

You mean usb<-->serial<-->rj45, right?
> The problem is that all info I found about this is that I'm supposed to
> select /dev/ttyUSB0 or similar device for connecting.

Which distro? If you using recognized hardware, udev should create
the /dev/usb/ttyUSBxx
when device is plugged in. There can be some cases where you need to manually
load the modules and do the
mknod /dev/usb/ttyUSB0 c 188 0
but should not be necessary or desired on a modern distro.

Watch the output of the 'dmesg' command, run dmesg before and after
plugging in the USB,
within a few seconds, dmesg should show the name of a device that has been
attached, if it is detected, and that it is a usb serial device, if
dmesg does not show anything new,
then device is broken or you need drivers, and you need to know what
model/chip
serial device you have, so you can find the right
driver, or get the drivers from the manufacturer.

If the manufacturer can't provide a proper driver, and you need to replace..
I am a big fan of the Prolific PL2303 chip based dongles, because
there are open source drivers in the Linux kernel proper and open
source OSX drivers as well,
Linux kernel should have those if built using CONFIG_USB_SERIAL_PL2303.

which is the default for major distributions for the past 5 years at least
Look for usbserial.ko and pl2303.ko files, in your modules directory

You might want to check the general state of which USB modules you
have with your installed kernel.

for i in /lib/modules/$(uname -r)/kernel/drivers/usb/serial/*.ko ; do
modinfo $i ; done|grep description

--
-JH
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