diff --git a/sam3s_example/simtrace/simtrace.h b/sam3s_example/simtrace/simtrace.h
index dd58e997..69892f7e 100644
--- a/sam3s_example/simtrace/simtrace.h
+++ b/sam3s_example/simtrace/simtrace.h
@@ -1,5 +1,5 @@
 
 // FIXME: static function definitions
-uint32_t _ISO7816_GetChar( uint8_t *pCharToReceive );
-uint32_t _ISO7816_SendChar( uint8_t CharToSend );
-void Phone_Master_Init( void );
+extern uint32_t _ISO7816_GetChar( uint8_t *pCharToReceive );
+extern uint32_t _ISO7816_SendChar( uint8_t CharToSend );
+extern void Phone_Master_Init( void );