private int _DisconnectDevice()
        {
            if (iHandle == 0)
            {
                return(0);
            }

            AardvarkApi.aa_close(iHandle);

            iHandle                = 0;
            tbPort.ReadOnly        = false;
            tbBitrate.ReadOnly     = false;
            cbConnectState.Checked = false;

            return(0);
        }