This USB-to-USB link cable is based on the Prolific PL2501 chipset, which has zero vendor and kernel support. It SHOULD be possible to add its hardware ID (067B:2501) to the plusb.c driver and recompile it, because the PL2501 chipset supports PL2301 compatibility mode. Someone on the net has done it [1] and it sort of works. However, I lack the knowledge to try this myself.

[1] http://www.mail-archive.com/linux-usb-devel@lists.sourceforge.net/msg42707.html

Go in your kernel directory. Open: ./drivers/usb/net/plusb.c and search for 067.

You should see:

static const struct usb_device_id products [] = {
{
USB_DEVICE(0x067b, 0x0000), // PL-2301
.driver_info = (unsigned long) &prolific_info,
}, {
USB_DEVICE(0x067b, 0x0001), // PL-2302
.driver_info = (unsigned long) &prolific_info,
},

{ }, // END
};

Make it read:

static const struct usb_device_id products [] = {
{
USB_DEVICE(0x067b, 0x0000), // PL-2301
.driver_info = (unsigned long) &prolific_info,
}, {
USB_DEVICE(0x067b, 0x0001), // PL-2302
.driver_info = (unsigned long) &prolific_info,
}, {
USB_DEVICE(0x067b, 0x2501), // PL-2501
.driver_info = (unsigned long) &prolific_info,
},

{ }, // END
};

Save the file and do: make modules && make modules_install

Cheers!