Comment 11 for bug 237357

I installed Ubuntu 9.1 four days ago and need to use my USB to RS232 adapter. Please note I am new to Linux.

Running Ubuntu 9.10
$ uname -r
2.6.31-20-generic

Plugged in my IOgear GUC232A USB to RS232 adapter
Following: http://blog.mypapit.net/2008/05/how-to-use-usb-serial-port-converter-in-ubuntu.html

$ lsusb
Bus 005 Device 002: ID 0557:2008 ATEN International Co., Ltd UC-232A Serial Port [pl2303]

$ sudo modprobe usbserial vendor=0x0557 product=0x2008

$dmesg
[ 20.536583] USB Serial support registered for pl2303
[ 20.536610] pl2303 5-1:1.0: pl2303 converter detected
[ 20.551884] usb 5-1: pl2303 converter now attached to ttyUSB0
[ 20.551908] usbcore: registered new interface driver pl2303
[ 20.551910] pl2303: Prolific PL2303 USB to serial adaptor driver

$ sudo gedit /etc/modules usbserial vendor=0x0557 product=0x2008

rebooted

Installed GtkTerm and selected Port: /dev/ttyUSB0 and serial communications worked.

Next day booted Ubuntu then executed GtkTerm and serial communications did not work. Nothing changed when lsusb and dmesg were executed. Removed and reinserted the USB to RS232 adapter and nothing. Rebooted....nothing.

$ sudo lsusb -v -d 0557:2008
Bus 005 Device 002: ID 0557:2008 ATEN International Co., Ltd UC-232A Serial Port [pl2303]
Device Descriptor:
  bMaxPacketSize0 64

With Synaptic Package Manager I removed modem-manager rebooted/reinserted the USB to RS232 adapter nothing. I then removed Brltty rebooted/reinserted but still nothing, no serial communications. Everything looked correct when lsusb and dmesg were executed.

Edited /etc/modules and commented the line "usbserial vendor=0x0557 product=0x2008"
rebooted and GtkTerm serial communication works!

I'm glad serial communications is now working. The site
http://manpages.ubuntu.com/manpages/karmic/en/man4/uplcom.4freebsd.html
indicates the support for this device is built into Ubuntu 9.10 but I don't understand how linux knows to use "usbserial vendor=0x0557 product=0x2008" if it is commented in /etc/modules.

$ sudo grep -i -R -l 0557 /etc/*
/etc/alternatives/net
grep: /etc/blkid.tab: No such file or directory
/etc/brltty/zh-tw.ctb
/etc/modules