diff --git a/avr/devices/n26/defs.asm b/avr/devices/n26/defs.asm
index 0b4a2fd..7bfd6c1 100644
--- a/avr/devices/n26/defs.asm
+++ b/avr/devices/n26/defs.asm
@@ -47,6 +47,15 @@
 .equ LED_SIMPLE_PINNUM  = PORTA3
 
 
+; ---------------------------------------------------------------------------
+; LED Activity module
+
+.equ LED_ACTIVITY_DDR     = DDRA
+.equ LED_ACTIVITY_PORT    = PORTA
+.equ LED_ACTIVITY_PORTIN  = PINA
+.equ LED_ACTIVITY_PINNUM  = PORTA3
+
+
 
 ; ---------------------------------------------------------------------------
 ; COM module
diff --git a/avr/devices/n26/main/main.asm b/avr/devices/n26/main/main.asm
index 63abdc6..de2c1c2 100644
--- a/avr/devices/n26/main/main.asm
+++ b/avr/devices/n26/main/main.asm
@@ -61,7 +61,8 @@
 
 ; #define MODULES_TIMER
 #define MODULES_CLOCK
-#define MODULES_LED_SIMPLE
+;#define MODULES_LED_SIMPLE
+#define MODULES_LED_ACTIVITY
 #define MODULES_NETWORK
 ;#define MODULES_UART_BITBANG
 #define MODULES_COM2W
diff --git a/avr/devices/n27/defs.asm b/avr/devices/n27/defs.asm
index c1646cc..78787f9 100644
--- a/avr/devices/n27/defs.asm
+++ b/avr/devices/n27/defs.asm
@@ -48,6 +48,16 @@
 
 
 
+; ---------------------------------------------------------------------------
+; LED Activity module
+
+.equ LED_ACTIVITY_DDR     = DDRA
+.equ LED_ACTIVITY_PORT    = PORTA
+.equ LED_ACTIVITY_PORTIN  = PINA
+.equ LED_ACTIVITY_PINNUM  = PORTA3
+
+
+
 ; ---------------------------------------------------------------------------
 ; COM module
 
diff --git a/avr/devices/n27/main/main.asm b/avr/devices/n27/main/main.asm
index 9f9b7aa..e082309 100644
--- a/avr/devices/n27/main/main.asm
+++ b/avr/devices/n27/main/main.asm
@@ -61,7 +61,8 @@
 
 ; #define MODULES_TIMER
 #define MODULES_CLOCK
-#define MODULES_LED_SIMPLE
+;#define MODULES_LED_SIMPLE
+#define MODULES_LED_ACTIVITY
 #define MODULES_NETWORK
 ;#define MODULES_UART_BITBANG
 #define MODULES_COM2W
diff --git a/avr/devices/t03/defs.asm b/avr/devices/t03/defs.asm
index 14b690a..48650a8 100644
--- a/avr/devices/t03/defs.asm
+++ b/avr/devices/t03/defs.asm
@@ -49,6 +49,16 @@
 
 
 
+; ---------------------------------------------------------------------------
+; LED signal module
+
+.equ LED_SIGNAL_DDR     = DDRB
+.equ LED_SIGNAL_PORT    = PORTB
+.equ LED_SIGNAL_PORTIN  = PINB
+.equ LED_SIGNAL_PINNUM  = PORTB2
+
+
+
 ; ---------------------------------------------------------------------------
 ; COM module
 
diff --git a/avr/devices/t03/uartfd/main.asm b/avr/devices/t03/uartfd/main.asm
index ca3dbaf..9c2ed6d 100644
--- a/avr/devices/t03/uartfd/main.asm
+++ b/avr/devices/t03/uartfd/main.asm
@@ -51,6 +51,17 @@
 .equ TTYONUART1_IFACENUM = 2
 
 
+; debug
+
+.equ T03_FLAGS_ALLOC        = 0x01
+.equ T03_FLAGS_I1_SKIPPING  = 0x02
+.equ T03_FLAGS_I1_RESTARTED = 0x04
+.equ T03_FLAGS_ADDIN        = 0x08
+.equ T03_FLAGS_I1_ADDOUT    = 0x10
+.equ T03_FLAGS_I2_ADDOUT    = 0x20
+
+
+
 ; ---------------------------------------------------------------------------
 ; firmware settings including list of modules used
 
@@ -63,7 +74,8 @@
 ;#define MODULES_COM
 ;#define MODULES_COM_WITH_ADDR_PROTO
 ;#define MODULES_LED
-#define MODULES_LED_SIMPLE
+;#define MODULES_LED_SIMPLE
+#define MODULES_LED_SIGNAL
 ;#define MODULES_TWI_MASTER
 ;#define MODULES_LCD
 ;#define LCD_MINIMAL_FONT
@@ -250,10 +262,3 @@ onMessageReceived:
 .equ netInterfaceData2 = com2w_iface
 
 
-; debug
-push r18
-  push r19
-    rcall LedSimple_SetFastTiming
-  pop r19
-pop r18
-