Extract interface numbers into enums.

35 files changed, 204 insertions, 87 deletions

diff --git a/Projects/AVRISP-MKII/AVRISPDescriptors.c b/Projects/AVRISP-MKII/AVRISPDescriptors.c
index cb19051f4..c185cb9f4 100644
--- a/Projects/AVRISP-MKII/AVRISPDescriptors.c
+++ b/Projects/AVRISP-MKII/AVRISPDescriptors.c
@@ -101,7 +101,7 @@ AVRISP_USB_Descriptor_Configuration_t AVRISP_ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 0,
+			.InterfaceNumber        = INTERFACE_ID_AVRISP,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 2,
diff --git a/Projects/AVRISP-MKII/AVRISPDescriptors.h b/Projects/AVRISP-MKII/AVRISPDescriptors.h
index 2f1192384..68bb10359 100644
--- a/Projects/AVRISP-MKII/AVRISPDescriptors.h
+++ b/Projects/AVRISP-MKII/AVRISPDescriptors.h
@@ -86,16 +86,25 @@
 			USB_Descriptor_Endpoint_t                AVRISP_DataOutEndpoint;
 		} AVRISP_USB_Descriptor_Configuration_t;
 
+		/** Enum for the device interface descriptor IDs within the device. Each interface descriptor
+		 *  should have a unique ID index associated with it, which can be used to refer to the
+		 *  interface from other descriptors.
+		 */
+		enum InterfaceDescriptors_t
+		{
+			INTERFACE_ID_AVRISP = 0, /**< AVRISP interface descriptor ID */
+		};
+
 		/** Enum for the device string descriptor IDs within the device. Each string descriptor should
 		 *  have a unique ID index associated with it, which can be used to refer to the string from
 		 *  other descriptors.
 		 */
 		enum AVRISP_StringDescriptors_t
 		{
-		    AVRISP_STRING_ID_Language      = 0, /**< Supported Languages string descriptor ID (must be zero) */
-		    AVRISP_STRING_ID_Manufacturer  = 1, /**< Manufacturer string ID */
-		    AVRISP_STRING_ID_Product       = 2, /**< Product string ID */
-		    AVRISP_STRING_ID_Serial        = 3, /**< Serial number string ID */
+			AVRISP_STRING_ID_Language     = 0, /**< Supported Languages string descriptor ID (must be zero) */
+			AVRISP_STRING_ID_Manufacturer = 1, /**< Manufacturer string ID */
+			AVRISP_STRING_ID_Product      = 2, /**< Product string ID */
+			AVRISP_STRING_ID_Serial       = 3, /**< Serial number string ID */
 		};
 
 	/* External Variables: */
diff --git a/Projects/Benito/Benito.c b/Projects/Benito/Benito.c
index a89e6caf6..2ecee0711 100644
--- a/Projects/Benito/Benito.c
+++ b/Projects/Benito/Benito.c
@@ -62,7 +62,7 @@ USB_ClassInfo_CDC_Device_t VirtualSerial_CDC_Interface =
 	{
 		.Config =
 			{
-				.ControlInterfaceNumber   = 0,
+				.ControlInterfaceNumber   = INTERFACE_ID_CDC_CCI,
 				.DataINEndpoint           =
 					{
 						.Address          = CDC_TX_EPADDR,
diff --git a/Projects/Benito/Descriptors.c b/Projects/Benito/Descriptors.c
index ebb11cac5..8bd0907d5 100644
--- a/Projects/Benito/Descriptors.c
+++ b/Projects/Benito/Descriptors.c
@@ -90,7 +90,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 0,
+			.InterfaceNumber        = INTERFACE_ID_CDC_CCI,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 1,
@@ -141,7 +141,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 1,
+			.InterfaceNumber        = INTERFACE_ID_CDC_DCI,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 2,
diff --git a/Projects/Benito/Descriptors.h b/Projects/Benito/Descriptors.h
index 12be7bf9c..5c67e7174 100644
--- a/Projects/Benito/Descriptors.h
+++ b/Projects/Benito/Descriptors.h
@@ -81,15 +81,25 @@
 			USB_Descriptor_Endpoint_t                CDC_DataInEndpoint;
 		} USB_Descriptor_Configuration_t;
 
+		/** Enum for the device interface descriptor IDs within the device. Each interface descriptor
+		 *  should have a unique ID index associated with it, which can be used to refer to the
+		 *  interface from other descriptors.
+		 */
+		enum InterfaceDescriptors_t
+		{
+			INTERFACE_ID_CDC_CCI = 0, /**< CDC CCI interface descriptor ID */
+			INTERFACE_ID_CDC_DCI = 1, /**< CDC DCI interface descriptor ID */
+		};
+
 		/** Enum for the device string descriptor IDs within the device. Each string descriptor should
 		 *  have a unique ID index associated with it, which can be used to refer to the string from
 		 *  other descriptors.
 		 */
 		enum StringDescriptors_t
 		{
-		    STRING_ID_Language      = 0, /**< Supported Languages string descriptor ID (must be zero) */
-		    STRING_ID_Manufacturer  = 1, /**< Manufacturer string ID */
-		    STRING_ID_Product       = 2, /**< Product string ID */
+			STRING_ID_Language     = 0, /**< Supported Languages string descriptor ID (must be zero) */
+			STRING_ID_Manufacturer = 1, /**< Manufacturer string ID */
+			STRING_ID_Product      = 2, /**< Product string ID */
 		};
 
 	/* Function Prototypes: */
diff --git a/Projects/LEDNotifier/Descriptors.c b/Projects/LEDNotifier/Descriptors.c
index 1875bba01..f228c69ef 100644
--- a/Projects/LEDNotifier/Descriptors.c
+++ b/Projects/LEDNotifier/Descriptors.c
@@ -91,7 +91,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 0,
+			.InterfaceNumber        = INTERFACE_ID_CDC_CCI,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 1,
@@ -142,7 +142,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 1,
+			.InterfaceNumber        = INTERFACE_ID_CDC_DCI,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 2,
diff --git a/Projects/LEDNotifier/Descriptors.h b/Projects/LEDNotifier/Descriptors.h
index 363951c5b..ed19d84f8 100644
--- a/Projects/LEDNotifier/Descriptors.h
+++ b/Projects/LEDNotifier/Descriptors.h
@@ -79,15 +79,25 @@
 			USB_Descriptor_Endpoint_t                CDC_DataInEndpoint;
 		} USB_Descriptor_Configuration_t;
 
+		/** Enum for the device interface descriptor IDs within the device. Each interface descriptor
+		 *  should have a unique ID index associated with it, which can be used to refer to the
+		 *  interface from other descriptors.
+		 */
+		enum InterfaceDescriptors_t
+		{
+			INTERFACE_ID_CDC_CCI = 0, /**< CDC CCI interface descriptor ID */
+			INTERFACE_ID_CDC_DCI = 1, /**< CDC DCI interface descriptor ID */
+		};
+
 		/** Enum for the device string descriptor IDs within the device. Each string descriptor should
 		 *  have a unique ID index associated with it, which can be used to refer to the string from
 		 *  other descriptors.
 		 */
 		enum StringDescriptors_t
 		{
-		    STRING_ID_Language      = 0, /**< Supported Languages string descriptor ID (must be zero) */
-		    STRING_ID_Manufacturer  = 1, /**< Manufacturer string ID */
-		    STRING_ID_Product       = 2, /**< Product string ID */
+			STRING_ID_Language     = 0, /**< Supported Languages string descriptor ID (must be zero) */
+			STRING_ID_Manufacturer = 1, /**< Manufacturer string ID */
+			STRING_ID_Product      = 2, /**< Product string ID */
 		};
 
 	/* Function Prototypes: */
diff --git a/Projects/LEDNotifier/LEDNotifier.c b/Projects/LEDNotifier/LEDNotifier.c
index d6a8fdca3..e1d5dd97f 100644
--- a/Projects/LEDNotifier/LEDNotifier.c
+++ b/Projects/LEDNotifier/LEDNotifier.c
@@ -44,7 +44,7 @@ USB_ClassInfo_CDC_Device_t VirtualSerial_CDC_Interface =
 	{
 		.Config =
 			{
-				.ControlInterfaceNumber   = 0,
+				.ControlInterfaceNumber   = INTERFACE_ID_CDC_CCI,
 				.DataINEndpoint           =
 					{
 						.Address          = CDC_TX_EPADDR,
diff --git a/Projects/MIDIToneGenerator/Descriptors.c b/Projects/MIDIToneGenerator/Descriptors.c
index 5413f27f5..220d37dff 100644
--- a/Projects/MIDIToneGenerator/Descriptors.c
+++ b/Projects/MIDIToneGenerator/Descriptors.c
@@ -90,7 +90,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                   = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber          = 0,
+			.InterfaceNumber          = INTERFACE_ID_AudioControl,
 			.AlternateSetting         = 0,
 
 			.TotalEndpoints           = 0,
@@ -118,7 +118,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                   = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber          = 1,
+			.InterfaceNumber          = INTERFACE_ID_AudioStream,
 			.AlternateSetting         = 0,
 
 			.TotalEndpoints           = 2,
diff --git a/Projects/MIDIToneGenerator/Descriptors.h b/Projects/MIDIToneGenerator/Descriptors.h
index cb8789187..dab2fd5a6 100644
--- a/Projects/MIDIToneGenerator/Descriptors.h
+++ b/Projects/MIDIToneGenerator/Descriptors.h
@@ -79,15 +79,25 @@
 			USB_MIDI_Descriptor_Jack_Endpoint_t       MIDI_Out_Jack_Endpoint_SPC;
 		} USB_Descriptor_Configuration_t;
 
+		/** Enum for the device interface descriptor IDs within the device. Each interface descriptor
+		 *  should have a unique ID index associated with it, which can be used to refer to the
+		 *  interface from other descriptors.
+		 */
+		enum InterfaceDescriptors_t
+		{
+			INTERFACE_ID_AudioControl = 0, /**< Audio control interface descriptor ID */
+			INTERFACE_ID_AudioStream  = 1, /**< Audio stream interface descriptor ID */
+		};
+
 		/** Enum for the device string descriptor IDs within the device. Each string descriptor should
 		 *  have a unique ID index associated with it, which can be used to refer to the string from
 		 *  other descriptors.
 		 */
 		enum StringDescriptors_t
 		{
-		    STRING_ID_Language      = 0, /**< Supported Languages string descriptor ID (must be zero) */
-		    STRING_ID_Manufacturer  = 1, /**< Manufacturer string ID */
-		    STRING_ID_Product       = 2, /**< Product string ID */
+			STRING_ID_Language     = 0, /**< Supported Languages string descriptor ID (must be zero) */
+			STRING_ID_Manufacturer = 1, /**< Manufacturer string ID */
+			STRING_ID_Product      = 2, /**< Product string ID */
 		};
 
 	/* Function Prototypes: */
diff --git a/Projects/MIDIToneGenerator/MIDIToneGenerator.c b/Projects/MIDIToneGenerator/MIDIToneGenerator.c
index 662c815bc..ed2d33420 100644
--- a/Projects/MIDIToneGenerator/MIDIToneGenerator.c
+++ b/Projects/MIDIToneGenerator/MIDIToneGenerator.c
@@ -44,7 +44,7 @@ USB_ClassInfo_MIDI_Device_t Keyboard_MIDI_Interface =
 	{
 		.Config =
 			{
-				.StreamingInterfaceNumber = 1,
+				.StreamingInterfaceNumber = INTERFACE_ID_AudioStream,
 				.DataINEndpoint           =
 					{
 						.Address          = MIDI_STREAM_IN_EPADDR,
diff --git a/Projects/Magstripe/Descriptors.c b/Projects/Magstripe/Descriptors.c
index 680944092..c707c1cf6 100644
--- a/Projects/Magstripe/Descriptors.c
+++ b/Projects/Magstripe/Descriptors.c
@@ -105,7 +105,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 0x00,
+			.InterfaceNumber        = INTERFACE_ID_Keyboard,
 			.AlternateSetting       = 0x00,
 
 			.TotalEndpoints         = 1,
diff --git a/Projects/Magstripe/Descriptors.h b/Projects/Magstripe/Descriptors.h
index 0f4869fb7..46218fc2c 100644
--- a/Projects/Magstripe/Descriptors.h
+++ b/Projects/Magstripe/Descriptors.h
@@ -56,18 +56,27 @@
 			// Keyboard HID Interface
 			USB_Descriptor_Interface_t            HID_Interface; /**< Keyboard interface descriptor */
 			USB_HID_Descriptor_HID_t              HID_KeyboardHID; /**< Keyboard HID descriptor */
-	        USB_Descriptor_Endpoint_t             HID_ReportINEndpoint; /**< Keyboard key report endpoint descriptor */
+			USB_Descriptor_Endpoint_t             HID_ReportINEndpoint; /**< Keyboard key report endpoint descriptor */
 		} USB_Descriptor_Configuration_t;
 
+		/** Enum for the device interface descriptor IDs within the device. Each interface descriptor
+		 *  should have a unique ID index associated with it, which can be used to refer to the
+		 *  interface from other descriptors.
+		 */
+		enum InterfaceDescriptors_t
+		{
+			INTERFACE_ID_Keyboard = 0, /**< Keyboard interface descriptor ID */
+		};
+
 		/** Enum for the device string descriptor IDs within the device. Each string descriptor should
 		 *  have a unique ID index associated with it, which can be used to refer to the string from
 		 *  other descriptors.
 		 */
 		enum StringDescriptors_t
 		{
-		    STRING_ID_Language      = 0, /**< Supported Languages string descriptor ID (must be zero) */
-		    STRING_ID_Manufacturer  = 1, /**< Manufacturer string ID */
-		    STRING_ID_Product       = 2, /**< Product string ID */
+			STRING_ID_Language     = 0, /**< Supported Languages string descriptor ID (must be zero) */
+			STRING_ID_Manufacturer = 1, /**< Manufacturer string ID */
+			STRING_ID_Product      = 2, /**< Product string ID */
 		};
 
 	/* Macros: */
diff --git a/Projects/Magstripe/Magstripe.c b/Projects/Magstripe/Magstripe.c
index 8dba7370b..a0b6f1b01 100644
--- a/Projects/Magstripe/Magstripe.c
+++ b/Projects/Magstripe/Magstripe.c
@@ -56,7 +56,7 @@ USB_ClassInfo_HID_Device_t Keyboard_HID_Interface =
 	{
 		.Config =
 			{
-				.InterfaceNumber            = 0,
+				.InterfaceNumber            = INTERFACE_ID_Keyboard,
 				.ReportINEndpoint           =
 					{
 						.Address            = KEYBOARD_EPADDR,
diff --git a/Projects/MediaController/Descriptors.c b/Projects/MediaController/Descriptors.c
index 636bbb618..353e5fe2f 100644
--- a/Projects/MediaController/Descriptors.c
+++ b/Projects/MediaController/Descriptors.c
@@ -122,7 +122,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 0x00,
+			.InterfaceNumber        = INTERFACE_ID_HID,
 			.AlternateSetting       = 0x00,
 
 			.TotalEndpoints         = 1,
diff --git a/Projects/MediaController/Descriptors.h b/Projects/MediaController/Descriptors.h
index 9f889641e..827885de6 100644
--- a/Projects/MediaController/Descriptors.h
+++ b/Projects/MediaController/Descriptors.h
@@ -53,18 +53,27 @@
 			// Media Controller HID Interface
 			USB_Descriptor_Interface_t            HID_Interface;
 			USB_HID_Descriptor_HID_t              HID_MediaControlHID;
-	        USB_Descriptor_Endpoint_t             HID_ReportINEndpoint;
+			USB_Descriptor_Endpoint_t             HID_ReportINEndpoint;
 		} USB_Descriptor_Configuration_t;
 
+		/** Enum for the device interface descriptor IDs within the device. Each interface descriptor
+		 *  should have a unique ID index associated with it, which can be used to refer to the
+		 *  interface from other descriptors.
+		 */
+		enum InterfaceDescriptors_t
+		{
+			INTERFACE_ID_HID = 0, /**< HID interface descriptor ID */
+		};
+
 		/** Enum for the device string descriptor IDs within the device. Each string descriptor should
 		 *  have a unique ID index associated with it, which can be used to refer to the string from
 		 *  other descriptors.
 		 */
 		enum StringDescriptors_t
 		{
-		    STRING_ID_Language      = 0, /**< Supported Languages string descriptor ID (must be zero) */
-		    STRING_ID_Manufacturer  = 1, /**< Manufacturer string ID */
-		    STRING_ID_Product       = 2, /**< Product string ID */
+			STRING_ID_Language     = 0, /**< Supported Languages string descriptor ID (must be zero) */
+			STRING_ID_Manufacturer = 1, /**< Manufacturer string ID */
+			STRING_ID_Product      = 2, /**< Product string ID */
 		};
 
 	/* Macros: */
diff --git a/Projects/MediaController/MediaController.c b/Projects/MediaController/MediaController.c
index d12a21aac..bda252a55 100644
--- a/Projects/MediaController/MediaController.c
+++ b/Projects/MediaController/MediaController.c
@@ -47,7 +47,7 @@ USB_ClassInfo_HID_Device_t MediaControl_HID_Interface =
  	{
 		.Config =
 			{
-				.InterfaceNumber              = 0,
+				.InterfaceNumber              = INTERFACE_ID_HID,
 				.ReportINEndpoint             =
 					{
 						.Address              = MEDIACONTROL_HID_EPADDR,
diff --git a/Projects/RelayBoard/Descriptors.c b/Projects/RelayBoard/Descriptors.c
index c6b2d8f56..646f7ca08 100644
--- a/Projects/RelayBoard/Descriptors.c
+++ b/Projects/RelayBoard/Descriptors.c
@@ -91,7 +91,7 @@ const USB_Descriptor_Configuration_t PROGMEM RelayBoard_ConfigurationDescriptor
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 0,
+			.InterfaceNumber        = INTERFACE_ID_RelayBoard,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 0,
diff --git a/Projects/RelayBoard/Descriptors.h b/Projects/RelayBoard/Descriptors.h
index 97ed22516..c2fc16efa 100644
--- a/Projects/RelayBoard/Descriptors.h
+++ b/Projects/RelayBoard/Descriptors.h
@@ -54,16 +54,25 @@
 			USB_Descriptor_Interface_t            RelayBoardInterface;
 		} USB_Descriptor_Configuration_t;
 
+		/** Enum for the device interface descriptor IDs within the device. Each interface descriptor
+		 *  should have a unique ID index associated with it, which can be used to refer to the
+		 *  interface from other descriptors.
+		 */
+		enum InterfaceDescriptors_t
+		{
+			INTERFACE_ID_RelayBoard = 0, /**< Relay board interface descriptor ID */
+		};
+
 		/** Enum for the device string descriptor IDs within the device. Each string descriptor should
 		 *  have a unique ID index associated with it, which can be used to refer to the string from
 		 *  other descriptors.
 		 */
 		enum StringDescriptors_t
 		{
-		    STRING_ID_Language      = 0, /**< Supported Languages string descriptor ID (must be zero) */
-		    STRING_ID_Manufacturer  = 1, /**< Manufacturer string ID */
-		    STRING_ID_Product       = 2, /**< Product string ID */
-		    STRING_ID_Serial        = 3, /**< Serial number string ID */
+			STRING_ID_Language     = 0, /**< Supported Languages string descriptor ID (must be zero) */
+			STRING_ID_Manufacturer = 1, /**< Manufacturer string ID */
+			STRING_ID_Product      = 2, /**< Product string ID */
+			STRING_ID_Serial       = 3, /**< Serial number string ID */
 		};
 
 	/* Function Prototypes: */
diff --git a/Projects/SerialToLCD/Descriptors.c b/Projects/SerialToLCD/Descriptors.c
index 8a55f82a4..baf33c0ce 100644
--- a/Projects/SerialToLCD/Descriptors.c
+++ b/Projects/SerialToLCD/Descriptors.c
@@ -103,7 +103,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 0,
+			.InterfaceNumber        = INTERFACE_ID_CDC_CCI,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 1,
@@ -154,7 +154,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 1,
+			.InterfaceNumber        = INTERFACE_ID_CDC_DCI,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 2,
diff --git a/Projects/SerialToLCD/Descriptors.h b/Projects/SerialToLCD/Descriptors.h
index 5776098e3..f6619296d 100644
--- a/Projects/SerialToLCD/Descriptors.h
+++ b/Projects/SerialToLCD/Descriptors.h
@@ -80,15 +80,25 @@
 			USB_Descriptor_Endpoint_t                CDC_DataInEndpoint;
 		} USB_Descriptor_Configuration_t;
 
+		/** Enum for the device interface descriptor IDs within the device. Each interface descriptor
+		 *  should have a unique ID index associated with it, which can be used to refer to the
+		 *  interface from other descriptors.
+		 */
+		enum InterfaceDescriptors_t
+		{
+			INTERFACE_ID_CDC_CCI = 0, /**< CDC CCI interface descriptor ID */
+			INTERFACE_ID_CDC_DCI = 1, /**< CDC DCI interface descriptor ID */
+		};
+
 		/** Enum for the device string descriptor IDs within the device. Each string descriptor should
 		 *  have a unique ID index associated with it, which can be used to refer to the string from
 		 *  other descriptors.
 		 */
 		enum StringDescriptors_t
 		{
-		    STRING_ID_Language      = 0, /**< Supported Languages string descriptor ID (must be zero) */
-		    STRING_ID_Manufacturer  = 1, /**< Manufacturer string ID */
-		    STRING_ID_Product       = 2, /**< Product string ID */
+			STRING_ID_Language     = 0, /**< Supported Languages string descriptor ID (must be zero) */
+			STRING_ID_Manufacturer = 1, /**< Manufacturer string ID */
+			STRING_ID_Product      = 2, /**< Product string ID */
 		};
 
 	/* Function Prototypes: */
diff --git a/Projects/SerialToLCD/SerialToLCD.c b/Projects/SerialToLCD/SerialToLCD.c
index aac4fadfb..21a5d68cb 100644
--- a/Projects/SerialToLCD/SerialToLCD.c
+++ b/Projects/SerialToLCD/SerialToLCD.c
@@ -51,7 +51,7 @@ USB_ClassInfo_CDC_Device_t VirtualSerial_CDC_Interface =
 	{
 		.Config =
 			{
-				.ControlInterfaceNumber   = 0,
+				.ControlInterfaceNumber   = INTERFACE_ID_CDC_CCI,
 				.DataINEndpoint           =
 					{
 						.Address          = CDC_TX_EPADDR,
diff --git a/Projects/SerialToLCD/SerialToLCD.h b/Projects/SerialToLCD/SerialToLCD.h
index 22537d609..bafc03c27 100644
--- a/Projects/SerialToLCD/SerialToLCD.h
+++ b/Projects/SerialToLCD/SerialToLCD.h
@@ -37,28 +37,28 @@
 #ifndef _SERIALTOLCD_H_
 #define _SERIALTOLCD_H_
 
-    /* Includes: */
-        #include <avr/io.h>
-        #include <avr/wdt.h>
-        #include <avr/interrupt.h>
-        #include <avr/power.h>
+	/* Includes: */
+		#include <avr/io.h>
+		#include <avr/wdt.h>
+		#include <avr/interrupt.h>
+		#include <avr/power.h>
 
-        #include "Descriptors.h"
+		#include "Descriptors.h"
 		#include "Lib/HD44780.h"
 
-        #include <LUFA/Version.h>
-        #include <LUFA/Drivers/Misc/RingBuffer.h>
-        #include <LUFA/Drivers/USB/USB.h>
+		#include <LUFA/Version.h>
+		#include <LUFA/Drivers/Misc/RingBuffer.h>
+		#include <LUFA/Drivers/USB/USB.h>
 		#include <LUFA/Platform/Platform.h>
 
 	/* Macros: */
 		#define COMMAND_ESCAPE     0x1B
 
-    /* Function Prototypes: */
-        void SetupHardware(void);
+	/* Function Prototypes: */
+		void SetupHardware(void);
 
-        void EVENT_USB_Device_ConfigurationChanged(void);
-        void EVENT_USB_Device_ControlRequest(void);
+		void EVENT_USB_Device_ConfigurationChanged(void);
+		void EVENT_USB_Device_ControlRequest(void);
 
 #endif
 
diff --git a/Projects/TempDataLogger/Descriptors.c b/Projects/TempDataLogger/Descriptors.c
index 6ec6f64aa..452c4c6ec 100644
--- a/Projects/TempDataLogger/Descriptors.c
+++ b/Projects/TempDataLogger/Descriptors.c
@@ -109,7 +109,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 0,
+			.InterfaceNumber        = INTERFACE_ID_MassStorage,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 2,
@@ -145,7 +145,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 1,
+			.InterfaceNumber        = INTERFACE_ID_HID,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 1,
diff --git a/Projects/TempDataLogger/Descriptors.h b/Projects/TempDataLogger/Descriptors.h
index 91e238fc1..63c3fae02 100644
--- a/Projects/TempDataLogger/Descriptors.h
+++ b/Projects/TempDataLogger/Descriptors.h
@@ -56,15 +56,25 @@
 			USB_Descriptor_Endpoint_t             HID_ReportINEndpoint;
 		} USB_Descriptor_Configuration_t;
 
+		/** Enum for the device interface descriptor IDs within the device. Each interface descriptor
+		 *  should have a unique ID index associated with it, which can be used to refer to the
+		 *  interface from other descriptors.
+		 */
+		enum InterfaceDescriptors_t
+		{
+			INTERFACE_ID_MassStorage = 0, /**< Mass storage interface descriptor ID */
+			INTERFACE_ID_HID         = 1, /**< HID interface descriptor ID */
+		};
+
 		/** Enum for the device string descriptor IDs within the device. Each string descriptor should
 		 *  have a unique ID index associated with it, which can be used to refer to the string from
 		 *  other descriptors.
 		 */
 		enum StringDescriptors_t
 		{
-		    STRING_ID_Language      = 0, /**< Supported Languages string descriptor ID (must be zero) */
-		    STRING_ID_Manufacturer  = 1, /**< Manufacturer string ID */
-		    STRING_ID_Product       = 2, /**< Product string ID */
+			STRING_ID_Language     = 0, /**< Supported Languages string descriptor ID (must be zero) */
+			STRING_ID_Manufacturer = 1, /**< Manufacturer string ID */
+			STRING_ID_Product      = 2, /**< Product string ID */
 		};
 
 	/* Function Prototypes: */
diff --git a/Projects/TempDataLogger/TempDataLogger.c b/Projects/TempDataLogger/TempDataLogger.c
index bbbea47f2..66f933586 100644
--- a/Projects/TempDataLogger/TempDataLogger.c
+++ b/Projects/TempDataLogger/TempDataLogger.c
@@ -44,7 +44,7 @@ USB_ClassInfo_MS_Device_t Disk_MS_Interface =
 	{
 		.Config =
 			{
-				.InterfaceNumber           = 0,
+				.InterfaceNumber           = INTERFACE_ID_MassStorage,
 				.DataINEndpoint            =
 					{
 						.Address           = MASS_STORAGE_IN_EPADDR,
@@ -72,7 +72,7 @@ USB_ClassInfo_HID_Device_t Generic_HID_Interface =
 	{
 		.Config =
 			{
-				.InterfaceNumber              = 1,
+				.InterfaceNumber              = INTERFACE_ID_HID,
 				.ReportINEndpoint             =
 					{
 						.Address              = GENERIC_IN_EPADDR,
diff --git a/Projects/USBtoSerial/Descriptors.c b/Projects/USBtoSerial/Descriptors.c
index b2d228588..ea0a84a0c 100644
--- a/Projects/USBtoSerial/Descriptors.c
+++ b/Projects/USBtoSerial/Descriptors.c
@@ -91,7 +91,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 0,
+			.InterfaceNumber        = INTERFACE_ID_CDC_CCI,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 1,
@@ -142,7 +142,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 1,
+			.InterfaceNumber        = INTERFACE_ID_CDC_DCI,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 2,
diff --git a/Projects/USBtoSerial/Descriptors.h b/Projects/USBtoSerial/Descriptors.h
index 363951c5b..ed19d84f8 100644
--- a/Projects/USBtoSerial/Descriptors.h
+++ b/Projects/USBtoSerial/Descriptors.h
@@ -79,15 +79,25 @@
 			USB_Descriptor_Endpoint_t                CDC_DataInEndpoint;
 		} USB_Descriptor_Configuration_t;
 
+		/** Enum for the device interface descriptor IDs within the device. Each interface descriptor
+		 *  should have a unique ID index associated with it, which can be used to refer to the
+		 *  interface from other descriptors.
+		 */
+		enum InterfaceDescriptors_t
+		{
+			INTERFACE_ID_CDC_CCI = 0, /**< CDC CCI interface descriptor ID */
+			INTERFACE_ID_CDC_DCI = 1, /**< CDC DCI interface descriptor ID */
+		};
+
 		/** Enum for the device string descriptor IDs within the device. Each string descriptor should
 		 *  have a unique ID index associated with it, which can be used to refer to the string from
 		 *  other descriptors.
 		 */
 		enum StringDescriptors_t
 		{
-		    STRING_ID_Language      = 0, /**< Supported Languages string descriptor ID (must be zero) */
-		    STRING_ID_Manufacturer  = 1, /**< Manufacturer string ID */
-		    STRING_ID_Product       = 2, /**< Product string ID */
+			STRING_ID_Language     = 0, /**< Supported Languages string descriptor ID (must be zero) */
+			STRING_ID_Manufacturer = 1, /**< Manufacturer string ID */
+			STRING_ID_Product      = 2, /**< Product string ID */
 		};
 
 	/* Function Prototypes: */
diff --git a/Projects/USBtoSerial/USBtoSerial.c b/Projects/USBtoSerial/USBtoSerial.c
index 6df906340..84ec2befa 100644
--- a/Projects/USBtoSerial/USBtoSerial.c
+++ b/Projects/USBtoSerial/USBtoSerial.c
@@ -56,7 +56,7 @@ USB_ClassInfo_CDC_Device_t VirtualSerial_CDC_Interface =
 	{
 		.Config =
 			{
-				.ControlInterfaceNumber         = 0,
+				.ControlInterfaceNumber         = INTERFACE_ID_CDC_CCI,
 				.DataINEndpoint                 =
 					{
 						.Address                = CDC_TX_EPADDR,
diff --git a/Projects/Webserver/Descriptors.c b/Projects/Webserver/Descriptors.c
index 8fcba5cc8..b8acf42a2 100644
--- a/Projects/Webserver/Descriptors.c
+++ b/Projects/Webserver/Descriptors.c
@@ -105,7 +105,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 0,
+			.InterfaceNumber        = INTERFACE_ID_CDC_CCI,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 1,
@@ -156,7 +156,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 1,
+			.InterfaceNumber        = INTERFACE_ID_CDC_DCI,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 2,
@@ -192,7 +192,7 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor =
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 2,
+			.InterfaceNumber        = INTERFACE_ID_MassStorage,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 2,
diff --git a/Projects/Webserver/Descriptors.h b/Projects/Webserver/Descriptors.h
index 2c25512e4..c649cf56f 100644
--- a/Projects/Webserver/Descriptors.h
+++ b/Projects/Webserver/Descriptors.h
@@ -96,15 +96,26 @@
 			USB_Descriptor_Endpoint_t              MS_DataOutEndpoint;
 		} USB_Descriptor_Configuration_t;
 
+		/** Enum for the device interface descriptor IDs within the device. Each interface descriptor
+		 *  should have a unique ID index associated with it, which can be used to refer to the
+		 *  interface from other descriptors.
+		 */
+		enum InterfaceDescriptors_t
+		{
+			INTERFACE_ID_CDC_CCI     = 0, /**< CDC CCI interface descriptor ID */
+			INTERFACE_ID_CDC_DCI     = 1, /**< CDC DCI interface descriptor ID */
+			INTERFACE_ID_MassStorage = 2, /**< Mass storage interface descriptor ID */
+		};
+
 		/** Enum for the device string descriptor IDs within the device. Each string descriptor should
 		 *  have a unique ID index associated with it, which can be used to refer to the string from
 		 *  other descriptors.
 		 */
 		enum StringDescriptors_t
 		{
-		    STRING_ID_Language      = 0, /**< Supported Languages string descriptor ID (must be zero) */
-		    STRING_ID_Manufacturer  = 1, /**< Manufacturer string ID */
-		    STRING_ID_Product       = 2, /**< Product string ID */
+			STRING_ID_Language     = 0, /**< Supported Languages string descriptor ID (must be zero) */
+			STRING_ID_Manufacturer = 1, /**< Manufacturer string ID */
+			STRING_ID_Product      = 2, /**< Product string ID */
 		};
 
 	/* Function Prototypes: */
diff --git a/Projects/Webserver/USBDeviceMode.c b/Projects/Webserver/USBDeviceMode.c
index 7d5beb93a..f889b6be6 100644
--- a/Projects/Webserver/USBDeviceMode.c
+++ b/Projects/Webserver/USBDeviceMode.c
@@ -44,7 +44,7 @@ USB_ClassInfo_RNDIS_Device_t Ethernet_RNDIS_Interface_Device =
 	{
 		.Config =
 			{
-				.ControlInterfaceNumber         = 0,
+				.ControlInterfaceNumber         = INTERFACE_ID_CDC_CCI,
 				.DataINEndpoint                 =
 					{
 						.Address                = CDC_TX_EPADDR,
@@ -76,7 +76,7 @@ USB_ClassInfo_MS_Device_t Disk_MS_Interface =
 	{
 		.Config =
 			{
-				.InterfaceNumber                = 2,
+				.InterfaceNumber                = INTERFACE_ID_MassStorage,
 				.DataINEndpoint                 =
 					{
 						.Address                = MASS_STORAGE_IN_EPADDR,
diff --git a/Projects/XPLAINBridge/USARTDescriptors.c b/Projects/XPLAINBridge/USARTDescriptors.c
index 0e0ac8534..b1bfd4e81 100644
--- a/Projects/XPLAINBridge/USARTDescriptors.c
+++ b/Projects/XPLAINBridge/USARTDescriptors.c
@@ -91,7 +91,7 @@ const USART_USB_Descriptor_Configuration_t PROGMEM USART_ConfigurationDescriptor
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 0,
+			.InterfaceNumber        = INTERFACE_ID_CDC_CCI,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 1,
@@ -142,7 +142,7 @@ const USART_USB_Descriptor_Configuration_t PROGMEM USART_ConfigurationDescriptor
 		{
 			.Header                 = {.Size = sizeof(USB_Descriptor_Interface_t), .Type = DTYPE_Interface},
 
-			.InterfaceNumber        = 1,
+			.InterfaceNumber        = INTERFACE_ID_CDC_DCI,
 			.AlternateSetting       = 0,
 
 			.TotalEndpoints         = 2,
diff --git a/Projects/XPLAINBridge/USARTDescriptors.h b/Projects/XPLAINBridge/USARTDescriptors.h
index 954867c18..130c695b9 100644
--- a/Projects/XPLAINBridge/USARTDescriptors.h
+++ b/Projects/XPLAINBridge/USARTDescriptors.h
@@ -81,22 +81,32 @@
 			USB_Descriptor_Endpoint_t                CDC_DataInEndpoint;
 		} USART_USB_Descriptor_Configuration_t;
 
+		/** Enum for the device interface descriptor IDs within the device. Each interface descriptor
+		 *  should have a unique ID index associated with it, which can be used to refer to the
+		 *  interface from other descriptors.
+		 */
+		enum USART_InterfaceDescriptors_t
+		{
+			INTERFACE_ID_CDC_CCI = 0, /**< CDC CCI interface descriptor ID */
+			INTERFACE_ID_CDC_DCI = 1, /**< CDC DCI interface descriptor ID */
+		};
+
 		/** Enum for the device string descriptor IDs within the device. Each string descriptor should
 		 *  have a unique ID index associated with it, which can be used to refer to the string from
 		 *  other descriptors.
 		 */
 		enum USART_StringDescriptors_t
 		{
-		    USART_STRING_ID_Language      = 0, /**< Supported Languages string descriptor ID (must be zero) */
-		    USART_STRING_ID_Manufacturer  = 1, /**< Manufacturer string ID */
-		    USART_STRING_ID_Product       = 2, /**< Product string ID */
+			USART_STRING_ID_Language     = 0, /**< Supported Languages string descriptor ID (must be zero) */
+			USART_STRING_ID_Manufacturer = 1, /**< Manufacturer string ID */
+			USART_STRING_ID_Product      = 2, /**< Product string ID */
 		};
 
 	/* Function Prototypes: */
 		uint16_t USART_GetDescriptor(const uint16_t wValue,
 		                             const uint8_t wIndex,
 		                             const void** const DescriptorAddress,
-									 uint8_t* const DescriptorMemorySpace);
+		                             uint8_t* const DescriptorMemorySpace);
 
 #endif
 
diff --git a/Projects/XPLAINBridge/XPLAINBridge.c b/Projects/XPLAINBridge/XPLAINBridge.c
index 2ef1d20ee..1c63b71d8 100644
--- a/Projects/XPLAINBridge/XPLAINBridge.c
+++ b/Projects/XPLAINBridge/XPLAINBridge.c
@@ -47,7 +47,7 @@ USB_ClassInfo_CDC_Device_t VirtualSerial_CDC_Interface =
 	{
 		.Config =
 			{
-				.ControlInterfaceNumber         = 0,
+				.ControlInterfaceNumber         = INTERFACE_ID_CDC_CCI,
 				.DataINEndpoint                 =
 					{
 						.Address                = CDC_TX_EPADDR,