diff --git a/config.default.h b/config.default.h
index d4e967c..d3fbe3c 100644
--- a/config.default.h
+++ b/config.default.h
@@ -38,10 +38,10 @@
 	#define	F_CPU	16000000UL
 #endif
 
-/** \def HOST
+/** \def MOTHERBOARD
 	This is the motherboard, as opposed to the extruder. See extruder/ directory for GEN3 extruder firmware
 */
-#define	HOST
+#define	MOTHERBOARD
 
 
 /** \def STEPS_PER_M
diff --git a/config.gen3.h b/config.gen3.h
index 89195f6..1be5c41 100644
--- a/config.gen3.h
+++ b/config.gen3.h
@@ -39,10 +39,10 @@
 	#define	F_CPU	16000000UL
 #endif
 
-/** \def HOST
+/** \def MOTHERBOARD
 	This is the motherboard, as opposed to the extruder. See extruder/ directory for GEN3 extruder firmware
 */
-#define	HOST
+#define	MOTHERBOARD
 
 
 /** \def STEPS_PER_M
diff --git a/config.gen6.h b/config.gen6.h
index a5e9841..70b3613 100644
--- a/config.gen6.h
+++ b/config.gen6.h
@@ -40,10 +40,10 @@
 	#define	F_CPU	16000000UL
 #endif
 
-/** \def HOST
+/** \def MOTHERBOARD
 	This is the motherboard, as opposed to the extruder. See extruder/ directory for GEN3 extruder firmware
 */
-#define	HOST
+#define	MOTHERBOARD
 
 
 /** \def STEPS_PER_M
diff --git a/config.gen7-v1.1-v1.3.h b/config.gen7-v1.1-v1.3.h
index 97acd27..78b1d19 100644
--- a/config.gen7-v1.1-v1.3.h
+++ b/config.gen7-v1.1-v1.3.h
@@ -46,10 +46,10 @@
 	#define	F_CPU	20000000UL
 #endif
 
-/** \def HOST
+/** \def MOTHERBOARD
 	This is the motherboard, as opposed to the extruder. See extruder/ directory for GEN3 extruder firmware
 */
-#define	HOST
+#define	MOTHERBOARD
 
 
 /** \def STEPS_PER_M
diff --git a/config.gen7-v1.4.h b/config.gen7-v1.4.h
index 01a8785..65eb359 100644
--- a/config.gen7-v1.4.h
+++ b/config.gen7-v1.4.h
@@ -46,10 +46,10 @@
 	#define	F_CPU	20000000UL
 #endif
 
-/** \def HOST
+/** \def MOTHERBOARD
 	This is the motherboard, as opposed to the extruder. See extruder/ directory for GEN3 extruder firmware
 */
-#define	HOST
+#define	MOTHERBOARD
 
 
 /** \def STEPS_PER_M
diff --git a/config.ramps-v1.2.h b/config.ramps-v1.2.h
index 6582a42..7ad2140 100644
--- a/config.ramps-v1.2.h
+++ b/config.ramps-v1.2.h
@@ -40,10 +40,10 @@
 	#define	F_CPU	16000000UL
 #endif
 
-/** \def HOST
+/** \def MOTHERBOARD
 	This is the motherboard, as opposed to the extruder. See extruder/ directory for GEN3 extruder firmware
 */
-#define	HOST
+#define	MOTHERBOARD
 
 
 /** \def STEPS_PER_M
diff --git a/config.ramps-v1.3.h b/config.ramps-v1.3.h
index 928c023..e4da563 100644
--- a/config.ramps-v1.3.h
+++ b/config.ramps-v1.3.h
@@ -40,10 +40,10 @@
 	#define	F_CPU	16000000UL
 #endif
 
-/** \def HOST
+/** \def MOTHERBOARD
 	This is the motherboard, as opposed to the extruder. See extruder/ directory for GEN3 extruder firmware
 */
-#define	HOST
+#define	MOTHERBOARD
 
 
 /** \def STEPS_PER_M
diff --git a/config.sanguinololu-v1.1.h b/config.sanguinololu-v1.1.h
index 0213f70..224f93d 100644
--- a/config.sanguinololu-v1.1.h
+++ b/config.sanguinololu-v1.1.h
@@ -39,10 +39,10 @@
 	#define	F_CPU	16000000UL
 #endif
 
-/** \def HOST
+/** \def MOTHERBOARD
 	This is the motherboard, as opposed to the extruder. See extruder/ directory for GEN3 extruder firmware
 */
-#define	HOST
+#define	MOTHERBOARD
 
 
 /** \def STEPS_PER_M
diff --git a/config.sanguinololu-v1.2.h b/config.sanguinololu-v1.2.h
index abba822..fdc3a84 100644
--- a/config.sanguinololu-v1.2.h
+++ b/config.sanguinololu-v1.2.h
@@ -39,10 +39,10 @@
 	#define	F_CPU	16000000UL
 #endif
 
-/** \def HOST
+/** \def MOTHERBOARD
 	This is the motherboard, as opposed to the extruder. See extruder/ directory for GEN3 extruder firmware
 */
-#define	HOST
+#define	MOTHERBOARD
 
 
 /** \def STEPS_PER_M
diff --git a/config.teensy.h b/config.teensy.h
index 8f90610..03f0b8e 100644
--- a/config.teensy.h
+++ b/config.teensy.h
@@ -40,10 +40,10 @@
 	#define	F_CPU	16000000UL
 #endif
 
-/** \def HOST
+/** \def MOTHERBOARD
 	This is the motherboard, as opposed to the extruder. See extruder/ directory for GEN3 extruder firmware
 */
-#define	HOST
+#define	MOTHERBOARD
 
 
 /** \def STEPS_PER_M
diff --git a/intercom.c b/intercom.c
index 9186035..32c3816 100644
--- a/intercom.c
+++ b/intercom.c
@@ -32,7 +32,7 @@ volatile uint8_t	intercom_flags;
 
 void intercom_init(void)
 {
-#ifdef HOST
+#ifdef MOTHERBOARD
 	#if INTERCOM_BAUD > 38401
 		UCSR1A = MASK(U2X1);
 		UBRR1 = (((F_CPU / 8) / INTERCOM_BAUD) - 0.5);
@@ -69,7 +69,7 @@ uint16_t read_temperature(uint8_t index) {
 	return rx.packet.temp[index];
 }
 
-#ifdef HOST
+#ifdef MOTHERBOARD
 void set_dio(uint8_t index, uint8_t value) {
 	if (value)
 		tx.packet.dio |= (1 << index);
@@ -122,7 +122,7 @@ void start_send(void) {
 	packet_pointer = 0;
 
 	// actually start sending the packet
-	#ifdef HOST
+	#ifdef MOTHERBOARD
 		UCSR1B |= MASK(UDRIE1);
 	#else
 		UCSR0B |= MASK(UDRIE0);
@@ -134,7 +134,7 @@ void start_send(void) {
 */
 
 // receive data interrupt- stuff into rx
-#ifdef HOST
+#ifdef MOTHERBOARD
 ISR(USART1_RX_vect)
 #else
 ISR(USART_RX_vect)
@@ -146,7 +146,7 @@ ISR(USART_RX_vect)
 	// pull character
 	static uint8_t c;
 
-	#ifdef HOST
+	#ifdef MOTHERBOARD
 		c = UDR1;
 		UCSR1A &= ~MASK(FE1) & ~MASK(DOR1) & ~MASK(UPE1);
 	#else
@@ -172,7 +172,7 @@ ISR(USART_RX_vect)
 			// reset pointer
 			packet_pointer = 0;
 
-			#ifndef HOST
+			#ifndef MOTHERBOARD
 			if (rxcrc == _rx.packet.crc &&
 			    _rx.packet.controller_num == THIS_CONTROLLER_NUM){
 			#else
@@ -185,7 +185,7 @@ ISR(USART_RX_vect)
 				}
 			}
 
-			#ifndef HOST
+			#ifndef MOTHERBOARD
 				if (rx.packet.controller_num == THIS_CONTROLLER_NUM) {
 					if (rxcrc != _rx.packet.crc)
 						tx.packet.err = ERROR_BAD_CRC;
@@ -207,7 +207,7 @@ ISR(USART_RX_vect)
 }
 
 // finished transmitting interrupt- only enabled at end of packet
-#ifdef HOST
+#ifdef MOTHERBOARD
 ISR(USART1_TX_vect)
 #else
 ISR(USART_TX_vect)
@@ -220,7 +220,7 @@ ISR(USART_TX_vect)
 		disable_transmit();
 		packet_pointer = 0;
 		intercom_flags = (intercom_flags & ~FLAG_TX_IN_PROGRESS) | FLAG_TX_FINISHED;
-		#ifdef HOST
+		#ifdef MOTHERBOARD
 			UCSR1B &= ~MASK(TXCIE1);
 		#else
 			UCSR0B &= ~MASK(TXCIE0);
@@ -233,7 +233,7 @@ ISR(USART_TX_vect)
 }
 
 // tx queue empty interrupt- send next byte
-#ifdef HOST
+#ifdef MOTHERBOARD
 ISR(USART1_UDRE_vect)
 #else
 ISR(USART_UDRE_vect)
@@ -242,14 +242,14 @@ ISR(USART_UDRE_vect)
 	// save status register
 	uint8_t sreg_save = SREG;
 
-	#ifdef	HOST
+	#ifdef	MOTHERBOARD
 	UDR1 = _tx.data[packet_pointer++];
 	#else
 	UDR0 = _tx.data[packet_pointer++];
 	#endif
 
 	if (packet_pointer >= sizeof(intercom_packet_t)) {
-		#ifdef HOST
+		#ifdef MOTHERBOARD
 			UCSR1B &= ~MASK(UDRIE1);
 			UCSR1B |= MASK(TXCIE1);
 		#else
diff --git a/intercom.h b/intercom.h
index 0b754b8..d4dffc3 100644
--- a/intercom.h
+++ b/intercom.h
@@ -4,7 +4,7 @@
 #include	<stdint.h>
 #include	"config.h"
 
-#ifdef HOST
+#ifdef MOTHERBOARD
 	#define enable_transmit()			do { WRITE(TX_ENABLE_PIN,1);  UCSR1B &=~MASK(RXEN1); } while(0)
 	#define disable_transmit()			do { WRITE(TX_ENABLE_PIN,0);  UCSR1B &= ~(MASK(TXCIE1) | MASK(UDRIE1)); UCSR1B |= MASK(RXEN1); } while(0)
 #else
diff --git a/timer.c b/timer.c
index 19fec0d..f3a7f4a 100644
--- a/timer.c
+++ b/timer.c
@@ -16,7 +16,7 @@
 #include	"arduino.h"
 #include	"config.h"
 
-#ifdef	HOST
+#ifdef	MOTHERBOARD
 #include	"dda_queue.h"
 #endif
 
@@ -80,7 +80,7 @@ ISR(TIMER1_COMPB_vect) {
 	SREG = sreg_save;
 }
 
-#ifdef	HOST
+#ifdef	MOTHERBOARD
 
 /// comparator A is the step timer. It has higher priority then B.
 ISR(TIMER1_COMPA_vect) {
@@ -123,7 +123,7 @@ ISR(TIMER1_COMPA_vect) {
 	MEMORY_BARRIER();
 	SREG = sreg_save;
 }
-#endif /* ifdef HOST */
+#endif /* ifdef MOTHERBOARD */
 
 /// initialise timer and enable system clock interrupt.
 /// step interrupt is enabled later when we start using it
@@ -139,7 +139,7 @@ void timer_init()
 	TIMSK1 = MASK(OCIE1B);
 }
 
-#ifdef	HOST
+#ifdef	MOTHERBOARD
 /*! Specify how long until the step timer should fire.
 	\param delay in CPU ticks
 
@@ -230,4 +230,4 @@ void timer_stop() {
 	// disable all interrupts
 	TIMSK1 = 0;
 }
-#endif /* ifdef HOST */
+#endif /* ifdef MOTHERBOARD */