Press and hold button named BUT and connect the USB cable, you should see:

[ 2202.771973] usb 3-3: new full-speed USB device number 10 using xhci_hcd
[ 2202.900579] usb 3-3: New USB device found, idVendor=0403, idProduct=a662, bcdDevice= 1.80
[ 2202.900592] usb 3-3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 2202.900596] usb 3-3: Product: Stk500v2
[ 2202.900599] usb 3-3: Manufacturer: www.cpustick.com
[ 2202.925687] cdc_acm 3-3:1.0: ttyACM0: USB ACM device
[ 2202.925706] usbcore: registered new interface driver cdc_acm
[ 2202.925707] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters