What USB port am I connected to?

Derek Broughton news at pointerstop.ca
Mon Nov 5 20:45:20 UTC 2007


Alex Janssen wrote:

> John Dangler said the following on 11/02/2007 10:28 AM:
>>
>> And dmesg will tell you exactly what dev you're dealing with...
>>
>> Jack - BB
>>
>> ----- Original Message -----
>> From: ubuntu-users-bounces at lists.ubuntu.com
>> <ubuntu-users-bounces at lists.ubuntu.com>
>> To: ubuntu-users at lists.ubuntu.com <ubuntu-users at lists.ubuntu.com>
>> Sent: Fri Nov 02 10:00:22 2007
>> Subject: Re: What USB port am I connected to?
>>
>> John Dangler wrote:
>>
>> > On Fri, 2007-11-02 at 00:05 -0400, Alex Janssen wrote:
>> >> I want to communicate with a serial device over the USB that is not a
>> >> recognized device.  It is a PLC(programmable logic controller). How do
>> >> I
>> >> tell which USB device file to open?  i.e.; /dev/bus/usb/002/001 or
>> >> 002... .  Is there a way to tell what I'm plugged into?  Is there a
>> >> USB
>> >> howto for programmers?
>> >
>> > 2 ways that I know of....
>> > plug in the device
>> > go to a terminal, type dmesg and look at the last output...
>> > OR
>> > lsusb should also give you some indication
>>
>> lshal, and the various gui hal viewers, will give much more information
>> about the actual /dev name.  lsusb will only tell you which _bus_ it's on
>> (in the example /dev/bus/usb/002) but not the device number, because that
>> autoincrements every time something's plugged in.
>> --
>> derek
>>
>>
>> --
>> ubuntu-users mailing list
>> ubuntu-users at lists.ubuntu.com
>> Modify settings or unsubscribe at:
>> https://lists.ubuntu.com/mailman/listinfo/ubuntu-users
>>
> Thanks to all of you for your input on this.  I tried lsusb, lshal and
> dmesg.  dmesg provided the most useful information.  It showed the
> device as follows:
> 
> [   22.444000]
> /build/buildd/linux-source-2.6.22-2.6.22/drivers/usb/serial/usb-serial.c:
> USB Serial support registered for pl2303
> [   22.444000] pl2303 3-1:1.0: pl2303 converter detected
> [   22.444000] usb 3-1: pl2303 converter now attached to ttyUSB0
> [   22.444000] usbcore: registered new interface driver pl2303
> [   22.444000]
> /build/buildd/linux-source-2.6.22-2.6.22/drivers/usb/serial/pl2303.c:
> Prolific PL2303 USB to serial adaptor driver
> 
> I can open ttyUSB0 with my program and read/write.  I can just make a
> static assignment within my python program, but I think I'd like to make
> it more dynamic and have my program figure out which port it's on.

It's actually easier to write a udev rule - look for the one (that doesn't
actually work...) that sets up a symlink for Palm
devices: /etc/udev/rules.d/60-symlinks.rules
You can do something similar that would set a symlink from /dev/pl2303 to
whatever ttyUSB* device was actually being used.  Then your program just
opens /dev/pl2303.  The information you need to determine that it's a
pl2303 should be available from "lshal".
-- 
derek





More information about the ubuntu-users mailing list