.ProductID              = 0x204B,
        .ReleaseNumber          = VERSION_BCD(00.01),
 
-       .ManufacturerStrIndex   = 0x01,
-       .ProductStrIndex        = 0x02,
+       .ManufacturerStrIndex   = USART_STRING_ID_Manufacturer,
+       .ProductStrIndex        = USART_STRING_ID_Product,
        .SerialNumStrIndex      = USE_INTERNAL_SERIAL,
 
        .NumberOfConfigurations = FIXED_NUM_CONFIGURATIONS
        uint16_t    Size    = NO_DESCRIPTOR;
 
        *DescriptorMemorySpace = MEMSPACE_FLASH;
-       
+
        switch (DescriptorType)
        {
                case DTYPE_Device:
                case DTYPE_String:
                        switch (DescriptorNumber)
                        {
-                               case 0x00:
+                               case USART_STRING_ID_Language:
                                        Address = &USART_LanguageString;
                                        Size    = pgm_read_byte(&USART_LanguageString.Header.Size);
                                        break;
-                               case 0x01:
+                               case USART_STRING_ID_Manufacturer:
                                        Address = &USART_ManufacturerString;
                                        Size    = pgm_read_byte(&USART_ManufacturerString.Header.Size);
                                        break;
-                               case 0x02:
+                               case USART_STRING_ID_Product:
                                        Address = &USART_ProductString;
                                        Size    = pgm_read_byte(&USART_ProductString.Header.Size);
                                        break;