diff --git a/rtlplayground.c b/rtlplayground.c
index 8f9bb9c..e37751d 100644
--- a/rtlplayground.c
+++ b/rtlplayground.c
@@ -326,7 +326,7 @@ void print_byte(uint8_t a)
 void isr_ext0(void) __interrupt(0)
 {
 	EX0 = 0;	// Disable interrupt for the moment
-	//write_char('X');
+	write_char('X');
 	IT0 = 1;	// Trigger on falling edge of external interrupt
 	EX0 = 1;	// Re-enable interrupt
 }
@@ -341,7 +341,7 @@ void isr_ext1(void) __interrupt(2)
 {
 	// This flag should only be reset after all packets have been read
 	EX1 = 0;
-	//write_char('Y');
+	write_char('Y');
 	EX1 = 1;
 }
 
@@ -352,7 +352,7 @@ void isr_ext1(void) __interrupt(2)
 void isr_ext2(void) __interrupt(8)
 {
 	EXIF &= 0xef;	// Clear IRQ flag (bit 7) in EXIF
-	//write_char('Z');
+	write_char('Z');
 	PCON |= 1; // Enter Idle mode until interrupt occurs
 }
 
@@ -363,7 +363,7 @@ void isr_ext2(void) __interrupt(8)
 void isr_ext3(void) __interrupt(9)
 {
 	EXIF &= 0xdf;	// Clear IRQ flag (bit 6) in EXIF
-	//write_char('W');
+	write_char('W');
 }
 
 // Timer2: handles system tick.