Using USB devices locally on the client

It may be necessary to use certain USB devices always locally on the client. This is configured using the so-called Device Use Local List. The Device Use Local List is a list of filters. Each entry in the Use Local List is a filter representing a specific group of USB devices which are to be used locally by the client (see also the USB Device Filter Lists section).

Starting with Version 1.5.x of CP-Link 3 the configuration of the Use Local List is done on the host PC

Up to version 1.4.x of CP-Link 3 the Device Use Local List has been configured by editing the registry on the client itself. Starting with Version 1.5.x of CP-Link 3 the configuration is done on the host PC (see also the Client Configuration section)

Adding devices to the Device Use Local List (up to Version 1.4.x of CP-Link 3)

The Device Use Local :ist is stored in the registry of the client under the key HKEY_LOCAL_MACHINE\SOFTWARE\Beckhoff\CP-Link 3\UsbDeviceServer\UseLocalList. Under this key the nListEntryCount value gives the number of list entries. For each entry in the list a sub-key is created, the name of which is its eight-character hexadecimal index (zero-based). In each subkey a filter can be defined using the "VendorId", "ProductId", "InterfaceClass", "InterfaceSubClass" and "InterfaceProtocol" values, which represents a group of USB devices.

Here for example, is a list with one entry which represents all USB mass storage devices.

[HKEY_LOCAL_MACHINE\SOFTWARE\Beckhoff\CP-Link 3\UsbDeviceServer\UseLocalList]
"nListEntryCount" = dword:00000001


[HKEY_LOCAL_MACHINE\SOFTWARE\Beckhoff\CP-Link 3\UsbDeviceServer\UseLocalList\00000000]
"Name" = "Mass Storage"
"VendorId" = dword:00000000
"ProductId" = dword:00000000
"InterfaceClass" = dword:00000008
"InterfaceSubClass" = dword:00000000
"InterfaceProtocol" = dword:00000000

Example registry files

Some examples are stored in the program directory of the host PC in the CE\Regfiles subfolder. From Version 1.1.19 the example registry files are also copied to the client by the CAB file installation. They are in the "\Hard Disk\Regfiles\Samples\CP-Link 3" directory. The values from a registry file can be transferred to the registry by double-clicking on the file in Windows CE Explorer.

Removing devices from the Device Use Local List (up to Version 1.4.x of CP-Link 3)

If an entry should be removed from the Device Use Local List, the corresponding subkey must be removed from the registry first. In addition the nListEntryCount value must be modified and it must be ensured that the remaining subkeys for the list entries beginning with 00000000 (eight-digit hexadecimal zero) are continuously numbered in ascending numerical order.