USB to serial port - device not accepting address 7, error "-71

[bp112]

When I plug in a USB to serial port, I cannot find /dev/ttyUSB

A check with dmesg shows:

[ 178.590357] usb 5-2: new full speed USB device using uhci_hcd and address 2
[ 179.106108] usb 5-2: device not accepting address 2, error -71
[ 179.208077] usb 5-2: new full speed USB device using uhci_hcd and address 3
[ 179.355155] usb 5-2: New USB device found, idVendor=067b, idProduct=2303
[ 179.355165] usb 5-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 179.355173] usb 5-2: Product: USB-Serial Controller
[ 179.355177] usb 5-2: Manufacturer: Prolific Technology Inc.
[ 179.454118] hub 5-0:1.0: port 2 disabled by hub (EMI?), re-enabling...
[ 179.454128] usb 5-2: USB disconnect, address 3
[ 179.472271] usbcore: registered new interface driver usbserial
[ 179.472293] USB Serial support registered for generic
[ 179.660061] usb 5-2: new full speed USB device using uhci_hcd and address 4
[ 180.176290] usb 5-2: device not accepting address 4, error -71
[ 180.278310] usb 5-2: new full speed USB device using uhci_hcd and address 5
[ 180.792129] usb 5-2: device not accepting address 5, error -71
[ 180.894290] usb 5-2: new full speed USB device using uhci_hcd and address 6
[ 181.302135] usb 5-2: device not accepting address 6, error -71
[ 181.404086] usb 5-2: new full speed USB device using uhci_hcd and address 7
[ 181.812292] usb 5-2: device not accepting address 7, error -71
[ 181.812322] hub 5-0:1.0: unable to enumerate USB device on port 2
[ 181.812434] usbcore: registered new interface driver usbserial_generic
[ 181.812440] usbserial: USB Serial Driver core
[ 181.927052] USB Serial support registered for pl2303
[ 181.927093] usbcore: registered new interface driver pl2303
[ 181.927095] pl2303: Prolific PL2303 USB to serial adaptor driver

I tried unplug then run lsusb and replug in and lsusb, it did not show any new devices.

Any idea what's going on?

Thanks in advance.

[alexeik]

Do you connect this USB device to USB hub?

[bp112]

Sorry for late reply.
Yes... I connected to it although I didn't connect anything to the serial end.
Is that the problem?


Thanks.

[alexeik]

I had symptoms like this, when I connected my usb->serial adapter to hub. When I used usb port on back side of my PC I had a success.
Anyway, it is easy to check - just connect your adapter to bare USB connector.

[bp112]

I did not use a USB hub.... it was directly plug-in to my computer USB port.
So far still no luck...