The Class of Device value contains a Device part which describes the primary service that the device provides, and a Service part which is a set of flags indicating all the service types that the device supports, e.g. ObjectTransfer, Telephony, Audio etc. This property supports setting those flags; bits set in this value will be added to the host device’s CoD Service Class bits when the listener is active. For Win32 see MSDN — BTH_SET_SERVICE Structure

Note:Supported on Win32, but not supported on WindowsMobile/WinCE as there's no native API for it. The WindowCE section of MSDN mentions the Registry value COD at key HKEY_LOCAL_MACHINE\Software\Microsoft\Bluetooth\sys. However my (Jam) has value 0x920100 there but advertises a CoD of 0x100114, so its not clear how the values relate to each other.