diff --git a/converter/sun_usb/Makefile b/converter/sun_usb/Makefile
index f046bfdd..12eceb5e 100644
--- a/converter/sun_usb/Makefile
+++ b/converter/sun_usb/Makefile
@@ -11,8 +11,8 @@ TARGET_DIR = .
 SRC =	keymap.c \
 	matrix.c \
 	led.c \
-	command_extra.c \
-	protocol/serial_soft.c
+	command_extra.c
+
 
 CONFIG_H = config.h
 
@@ -64,8 +64,15 @@ MOUSEKEY_ENABLE = yes	# Mouse keys
 EXTRAKEY_ENABLE = yes	# Audio control and System control
 CONSOLE_ENABLE = yes	# Console for debug
 COMMAND_ENABLE = yes    # Commands for debug and configuration
+#HARDWARE_SERIAL = yes  # Use hardware serial (requires inverted serial, see README)
 #NKRO_ENABLE = yes	# USB Nkey Rollover
 
+ifdef HARDWARE_SERIAL
+	SRC := protocol/serial_uart.c $(SRC)
+	OPT_DEFS += -DHARDWARE_SERIAL
+else
+	SRC := protocol/serial_soft.c $(SRC)
+endif
 
 # Boot Section Size in bytes
 #   Teensy halfKay   512
diff --git a/converter/sun_usb/README b/converter/sun_usb/README
index 98340dd3..405a86ba 100644
--- a/converter/sun_usb/README
+++ b/converter/sun_usb/README
@@ -48,7 +48,9 @@ Frame format: 1-Start bit, 8-Data bits, No-Parity, 1-Stop bit
     To use AVR UART engine you need external inverter in front of RX and TX pin.
     Otherwise you can software serial routine to communicate the keyboard.
 
-This converter uses software method, you doesn't need any inverter part.
+This converter uses software method by default, so you don't need any inverter part.  But
+it can also be built with 'make HARDWARE_SERIAL=y' to enable hardware serial if there
+is an inverter present.  Good results have been obtained using a 74LS04 and hardware serial.
 
 
 Commands From System To Keyboard
diff --git a/converter/sun_usb/config.h b/converter/sun_usb/config.h
index 66036da9..414fd563 100644
--- a/converter/sun_usb/config.h
+++ b/converter/sun_usb/config.h
@@ -39,57 +39,88 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 /* legacy keymap support */
 #define USE_LEGACY_KEYMAP
 
-
-/* Serial(USART) configuration
- *     asynchronous, negative logic, 1200baud, no flow control
- *     1-start bit, 8-data bit, non parity, 1-stop bit
+/* HARDWARE_SERAIL assumes that a logic inverter (7404) is placed
+ * in front of RX/TX to produce the positive logic the MCU expects.
+ * The default is Software Serial.
  */
-#define SERIAL_SOFT_BAUD            1200
-#define SERIAL_SOFT_PARITY_NONE
-#define SERIAL_SOFT_BIT_ORDER_LSB
-#define SERIAL_SOFT_LOGIC_NEGATIVE
-/* RXD Port */
-#define SERIAL_SOFT_RXD_ENABLE
-#define SERIAL_SOFT_RXD_DDR         DDRD
-#define SERIAL_SOFT_RXD_PORT        PORTD
-#define SERIAL_SOFT_RXD_PIN         PIND
-#define SERIAL_SOFT_RXD_BIT         2
-#define SERIAL_SOFT_RXD_VECT        INT2_vect
-/* RXD Interupt */
-#ifdef SERIAL_SOFT_LOGIC_NEGATIVE
-/* enable interrupt: INT2(rising edge) */
-#define INTR_TRIG_EDGE   ((1<<ISC21)|(1<<ISC20))
-#else
-/* enable interrupt: INT2(falling edge) */
-#define INTR_TRIG_EDGE   ((1<<ISC21)|(0<<ISC20))
-#endif
-#define SERIAL_SOFT_RXD_INIT()      do { \
-    /* pin configuration: input with pull-up */ \
-    SERIAL_SOFT_RXD_DDR &= ~(1<<SERIAL_SOFT_RXD_BIT); \
-    SERIAL_SOFT_RXD_PORT |= (1<<SERIAL_SOFT_RXD_BIT); \
-    EICRA |= INTR_TRIG_EDGE; \
-    EIMSK |= (1<<INT2); \
-    sei(); \
-} while (0)
-#define SERIAL_SOFT_RXD_INT_ENTER()
-#define SERIAL_SOFT_RXD_INT_EXIT()  do { \
-    /* clear interrupt  flag */ \
-    EIFR = (1<<INTF2); \
-} while (0)
-#define SERIAL_SOFT_RXD_READ()      (SERIAL_SOFT_RXD_PIN&(1<<SERIAL_SOFT_RXD_BIT))
-/* TXD Port */
-#define SERIAL_SOFT_TXD_ENABLE
-#define SERIAL_SOFT_TXD_DDR         DDRD
-#define SERIAL_SOFT_TXD_PORT        PORTD
-#define SERIAL_SOFT_TXD_PIN         PIND
-#define SERIAL_SOFT_TXD_BIT         3
-#define SERIAL_SOFT_TXD_HI()        do { SERIAL_SOFT_TXD_PORT |=  (1<<SERIAL_SOFT_TXD_BIT); } while (0)
-#define SERIAL_SOFT_TXD_LO()        do { SERIAL_SOFT_TXD_PORT &= ~(1<<SERIAL_SOFT_TXD_BIT); } while (0)
-#define SERIAL_SOFT_TXD_INIT()      do { \
-    /* pin configuration: output */ \
-    SERIAL_SOFT_TXD_DDR |= (1<<SERIAL_SOFT_TXD_BIT); \
-    /* idle */ \
-    SERIAL_SOFT_TXD_ON(); \
-} while (0)
+#if defined(HARDWARE_SERIAL)
 
-#endif
+    /* Hardware Serial (USART) configuration
+     *     asynchronous, negative logic, 1200baud, no flow control
+     *     1-start bit, 8-data bit, non parity, 1-stop bit
+     *
+     */
+    #if defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega32U2__)
+    #define SERIAL_UART_BAUD       1200
+    #define SERIAL_UART_DATA       UDR1
+    #define SERIAL_UART_UBRR       ((F_CPU/(16UL*SERIAL_UART_BAUD))-1)
+    #define SERIAL_UART_RXD_VECT   USART1_RX_vect
+    #define SERIAL_UART_TXD_READY  (UCSR1A&(1<<UDRE1))
+    #define SERIAL_UART_INIT()     do { \
+        UBRR1L = (uint8_t) SERIAL_UART_UBRR;       /* baud rate */ \
+        UBRR1H = (uint8_t) (SERIAL_UART_UBRR>>8);  /* baud rate */ \
+        UCSR1B = (1<<RXCIE1) | (1<<RXEN1) | /* RX: interrupt, RX: enable */ \
+                 (1<<TXEN1);                /* TX: enable */ \
+        UCSR1C = (0<<UPM11) | (0<<UPM10) | /* parity: none(00), even(01), odd(11) */ \
+                 (0<<UCSZ12) | (1<<UCSZ11) | (1<<UCSZ10); /* data-8bit(011) */ \
+        sei(); \
+    } while(0)
+    #else
+    #   error "USART configuration is needed."
+    #endif
+
+#else
+    /* Software Serial configuration
+     *     asynchronous, negative logic, 1200baud, no flow control
+     *     1-start bit, 8-data bit, non parity, 1-stop bit
+     */
+    #define SERIAL_SOFT_BAUD            1200
+    #define SERIAL_SOFT_PARITY_NONE
+    #define SERIAL_SOFT_BIT_ORDER_LSB
+    #define SERIAL_SOFT_LOGIC_NEGATIVE
+    /* RXD Port */
+    #define SERIAL_SOFT_RXD_ENABLE
+    #define SERIAL_SOFT_RXD_DDR         DDRD
+    #define SERIAL_SOFT_RXD_PORT        PORTD
+    #define SERIAL_SOFT_RXD_PIN         PIND
+    #define SERIAL_SOFT_RXD_BIT         2
+    #define SERIAL_SOFT_RXD_VECT        INT2_vect
+    /* RXD Interupt */
+    #ifdef SERIAL_SOFT_LOGIC_NEGATIVE
+    /* enable interrupt: INT2(rising edge) */
+    #define INTR_TRIG_EDGE   ((1<<ISC21)|(1<<ISC20))
+    #else
+    /* enable interrupt: INT2(falling edge) */
+    #define INTR_TRIG_EDGE   ((1<<ISC21)|(0<<ISC20))
+    #endif
+    #define SERIAL_SOFT_RXD_INIT()      do { \
+        /* pin configuration: input with pull-up */ \
+        SERIAL_SOFT_RXD_DDR &= ~(1<<SERIAL_SOFT_RXD_BIT); \
+        SERIAL_SOFT_RXD_PORT |= (1<<SERIAL_SOFT_RXD_BIT); \
+        EICRA |= INTR_TRIG_EDGE; \
+        EIMSK |= (1<<INT2); \
+        sei(); \
+    } while (0)
+    #define SERIAL_SOFT_RXD_INT_ENTER()
+    #define SERIAL_SOFT_RXD_INT_EXIT()  do { \
+        /* clear interrupt  flag */ \
+        EIFR = (1<<INTF2); \
+    } while (0)
+    #define SERIAL_SOFT_RXD_READ()      (SERIAL_SOFT_RXD_PIN&(1<<SERIAL_SOFT_RXD_BIT))
+    /* TXD Port */
+    #define SERIAL_SOFT_TXD_ENABLE
+    #define SERIAL_SOFT_TXD_DDR         DDRD
+    #define SERIAL_SOFT_TXD_PORT        PORTD
+    #define SERIAL_SOFT_TXD_PIN         PIND
+    #define SERIAL_SOFT_TXD_BIT         3
+    #define SERIAL_SOFT_TXD_HI()        do { SERIAL_SOFT_TXD_PORT |=  (1<<SERIAL_SOFT_TXD_BIT); } while (0)
+    #define SERIAL_SOFT_TXD_LO()        do { SERIAL_SOFT_TXD_PORT &= ~(1<<SERIAL_SOFT_TXD_BIT); } while (0)
+    #define SERIAL_SOFT_TXD_INIT()      do { \
+        /* pin configuration: output */ \
+        SERIAL_SOFT_TXD_DDR |= (1<<SERIAL_SOFT_TXD_BIT); \
+        /* idle */ \
+        SERIAL_SOFT_TXD_ON(); \
+    } while (0)
+
+#endif //hardware serial
+#endif //config.h