diff --git a/dda_queue.c b/dda_queue.c
index 87effa7..9712160 100644
--- a/dda_queue.c
+++ b/dda_queue.c
@@ -3,7 +3,7 @@
 #include	<string.h>
 #include	<avr/interrupt.h>
 
-#include	"config.h" // for XONXOFF
+#include	"config.h"
 #include	"timer.h"
 #include	"serial.h"
 #include	"sermsg.h"
@@ -76,13 +76,6 @@ void enqueue(TARGET *t) {
 
 	mb_head = h;
 
-	#ifdef	XONXOFF
-	// If the queue has only two slots remaining, stop transmission. More
-	// characters might come in until the stop takes effect.
-	if (((mb_tail - mb_head - 1) & (MOVEBUFFER_SIZE - 1)) < (MOVEBUFFER_SIZE - 2))
-		xoff();
-	#endif
-
 	// fire up in case we're not running yet
 	if (timerInterruptIsEnabled() == 0)
 		next_move();
@@ -99,12 +92,6 @@ void next_move() {
 	}
 	else
 		disableTimerInterrupt();
-
-	#ifdef	XONXOFF
-	// restart transmission if the move buffer is only half full
-	if (((mb_tail - mb_head - 1) & (MOVEBUFFER_SIZE - 1)) > (MOVEBUFFER_SIZE / 2))
-		xon();
-	#endif
 }
 
 void print_queue() {
diff --git a/gcode.c b/gcode.c
index 2c5e717..aa8a1c2 100644
--- a/gcode.c
+++ b/gcode.c
@@ -411,17 +411,11 @@ void process_gcode_command(GCODE_COMMAND *gcmd) {
 
 			//	G4 - Dwell
 			case 4:
-				#ifdef	XONXOFF
-				xoff();
-				#endif
 				// wait for all moves to complete
 				for (;queue_empty() == 0;)
 					wd_reset();
 				// delay
 				delay_ms(gcmd->P);
-				#ifdef	XONXOFF
-				xon();
-				#endif
 				break;
 
 			//	G20 - inches as units
diff --git a/serial.c b/serial.c
index 233323c..f592973 100644
--- a/serial.c
+++ b/serial.c
@@ -2,6 +2,7 @@
 
 #include	<avr/interrupt.h>
 
+#include	"config.h" // for XONXOFF
 #include	"arduino.h"
 
 #define		BUFSIZE			64
@@ -94,6 +95,7 @@ ISR(USART0_RX_vect)
 		// the buffer has only 16 free characters left, so send an XOFF
 		// more characters might come in until the XOFF takes effect
 		flowflags = FLOWFLAG_SEND_XOFF | FLOWFLAG_STATE_XON;
+		// enable TX interrupt so we can send this character
 		UCSR0B |= MASK(UDRIE0);
 	}
 	#endif
@@ -214,29 +216,3 @@ void serial_writestr_P(PGM_P data)
 	while ((r = pgm_read_byte(&data[i++])))
 		serial_writechar(r);
 }
-
-#ifdef	XONXOFF
-void xon() {
-	// disable TX interrupt
-	UCSR0B &= ~MASK(UDRIE0);
-
-	if ((flowflags & FLOWFLAG_STATE_XON) == 0)
-		flowflags = FLOWFLAG_SEND_XON;
-	else
-		flowflags = FLOWFLAG_STATE_XON;	// purge a possible FLOWFLAG_SEND_XOFF
-
-	// enable TX interrupt so we can send this character
-	UCSR0B |= MASK(UDRIE0);
-}
-
-void xoff() {
-	UCSR0B &= ~MASK(UDRIE0);
-
-	if (flowflags & FLOWFLAG_STATE_XON)
-		flowflags = FLOWFLAG_SEND_XOFF | FLOWFLAG_STATE_XON;
-	else
-		flowflags = 0;
-
-	UCSR0B |= MASK(UDRIE0);
-}
-#endif
diff --git a/serial.h b/serial.h
index 982ffb9..cd6a54f 100644
--- a/serial.h
+++ b/serial.h
@@ -5,8 +5,6 @@
 #include	<avr/io.h>
 #include	<avr/pgmspace.h>
 
-#include	"config.h" // for XONXOFF
-
 // initialise serial subsystem
 void serial_init(void);
 
@@ -29,10 +27,4 @@ void serial_writestr(uint8_t *data);
 void serial_writeblock_P(PGM_P data, int datalen);
 void serial_writestr_P(PGM_P data);
 
-#ifdef	XONXOFF
-// XON/XOFF flow control
-void xon(void);
-void xoff(void);
-#endif
-
 #endif	/* _SERIAL_H */