BECKHOFF CP-Link3 - Manual (Page 49)

Page 49
USB Device Filter Lists
For each client a set of USB device filter lists can be defined - the so called Blacklist, Whitelist and Use Local List (see
also the Client Configuration section). Each entry in these lists represents a specific group of USB devices.
Device Blacklist
The host PC ignores USB devices with a matching entry in the Device Blacklist
If "Virtual-USB" is active and there is a matching Blacklist entry for a client's USB device, it is not going to be connected
to the host PC via "Virtual-USB". The USB device is not useable on the host PC as well as on the client.
Device Whitelist
A matching entry in the Device Whitelist overrides a match in the Device Blacklist. The host PC is not going to ignore
such a USB device even though it has a matching entry in the Blacklist.
If "Virtual-USB" is active and there is a matching Blacklist entry as well as a matching Whitelist entry for a client's USB
device, the Whitelist entry overrides the Blacklist entry and the device is going to be connected to the host PC via
"Virtual-USB" anyway. This may be useful to block a particular category of USB devices, e.g. HID - Human Input
Devices, but allow a sub-category of the blocked devices, e.g. keyboards.
Device Use Local List
USB devices with a matching entry in the Device Use Local List are used locally by the client.
If "Virtual-USB" is active and there is a matching Use Local List entry for a client's USB device, it is not going to be
connected to the host PC via "Virtual-USB". Instead the device can be used locally by the client.
Mode of action
The described device filter lists are applied for each client's USB device as follows:
Device Use Local List
The Use Local List is applied on the client itself. If there is a matching entry for the USB device, it is introduced to
the client's OS and can therefore be used locally on the client. On the other hand, if there is no matching entry for
the USB device, it is going to be connected to the host PC via "Virtual-USB". 1.
Device Blacklist
If there is no matching Use Local List entry for the USB device, the Device Blacklist is applied on the host PC. If
there is no matching entry for the USB device in the Blacklist, the device is introduced to the host's OS and can
therefore be used on the host PC. If there in turn is no matching entry for the USB device, it is not introduced to
the host's OS, but the Device Whitelist is going to be applied. 2.
Device Whitelist 3.
BECKHOFF CP-Link 3: Miscellaneous