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I have to use trendnet tu-s9 usb to serial converter to transmit some commands via RS232. But unfortunately I couldn't see USB-Serial converter as ttyUSB under "/dev/" path. I don't understand the issue as USB detecting under usb list please see the below "lsusb" output

*:~$ lsusb

Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub

Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Bus 002 Device 003: ID 0835:1601 Action Star Enterprise Co., Ltd

Bus 002 Device 004: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port*

When I locate USBSerial I could see USBSerial drivers installed.

*:~$ locate usbserial

/boot/grub/usbserial_common.mod

/boot/grub/usbserial_ftdi.mod

/boot/grub/usbserial_pl2303.mod

/lib/modules/3.2.0-4-686-pae/kernel/drivers/usb/serial/usbserial.ko

/lib/modules/3.2.0-4-rt-686-pae/kernel/drivers/usb/serial/usbserial.ko

/usr/lib/grub/i386-pc/usbserial_common.mod

/usr/lib/grub/i386-pc/usbserial_ftdi.mod

/usr/lib/grub/i386-pc/usbserial_pl2303.mod*

Though I have drivers and USB listed in usb list, I am not getting device path under /dev/ as ttyUSB. Is there any way to get it ?

Please help me in this issue.

Linux details which I am using:

*:~$ lsb_release -a

No LSB modules are available.

Distributor ID: Debian

Description: Debian GNU/Linux 7.8 (wheezy)

Release: 7.8

Codename: wheezy*

Many Thanks in Advance.

linuxman
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1 Answers1

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If you see your device in lsusb, please make note of the vendor id and product id

eg:- productID a000

lsusb |grep a000

Then in your udev rules add this line. These are from RHEL version. 

KERNEL=="ttyUSB*", SYSFS{idVendor}=="019c", SYSFS{idProduct}=="a000", MODE=="0660", SYMLINK+="your-device-name"

Now unplug and plug back your USB device or trigger a udev activity. You should see a device handle /dev/your-device-name

Also check 

/dev/input/by-id
/dev/input/by-path

dmesg is also a good tool to start debugging USB connect issues

PackedUp
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  • Thanks for your prompt reply. – linuxman Mar 16 '15 at 04:29
  • Thanks for prompt reply. I have added this ("SUBSYSTEM=="tty", ACTION=="add", DRIVERS=="?*", ATTR{idVendor}=="0x067b", ATTR{idProduct}=="0x2303", KERNEL=="ttyUSB", NAME="ttyusb0") rule in udev rules. But No luck yet. In demsg output as below shows usb details but not device handle path. please correct me If i am wrong [ 4189.301802] usb 2-1.4: New USB device found, idVendor=067b, idProduct=2303. – linuxman Mar 16 '15 at 04:48
  • You need a * in the Kernel parameter. (KERNEL=="ttyUSB*"). – PackedUp Mar 16 '15 at 11:40
  • I have added Kernel parameter (KERNEL=="ttyUSB*") but still no change. I have checked the dmesg log and I found that no driver loaded in the kernel. Could you please tell me how do I load this driver in to kernel? I am new to linux So please bare with my questions. Thanks a ton. – linuxman Mar 18 '15 at 10:38
  • I tried following command using modprobe but still no luck sudo modprobe usbserial vendor=0x067b product=0x2303 and output would be "FATAL: Module usbserial not found." – linuxman Mar 18 '15 at 11:13
  • Looks like the usbserial driver is not getting loaded. There should be a usbserial.ko file in your kernel modules. /lib/modules/`uname -r`/kernel/drivers/usb/serial/usbserial.ko. Try loading it by just issuing modprobe usbserial. Check to see if it is already loaded by running `lsusb |grep usbserail` – PackedUp Mar 18 '15 at 15:19
  • Yes, you are right there is no usbserial driver loaded. There is no usb folder at all under /lib/modules/uname -r/kernel/drivers/. Could you please tell me how do I get these drivers installed? – linuxman Mar 19 '15 at 12:15
  • Usually it come with the Linux distribution. Refer here https://wiki.debian.org/usbserial . Good luck. – PackedUp Mar 19 '15 at 16:03