diff --git a/fetapdtest.py b/fetapdtest.py
index 04b9893..099d1b9 100644
--- a/fetapdtest.py
+++ b/fetapdtest.py
@@ -34,6 +34,9 @@ class AbstractState(object):
 	
 	def on_call_ringing(self):
 		raise IllegalEventError()
+
+	def on_invalid_number(self):
+		raise IllegalEventError()
 	
 	def on_nummernschalter_input(self, num):
 		raise IllegalEventError()
@@ -125,6 +128,7 @@ class BusyBeepingState(AbstractState):
 		return ForgottenState
 	
 	def on_gabelschalter_down(self):
+		self.__on_leave()
 		return IdleState
 
 class CallRunningState(AbstractState):
@@ -154,6 +158,10 @@ class ConnectingState(AbstractState):
 	def on_call_accepted(self):
 		return CallRunningState
 
+	def on_invalid_number(self):
+		# TODO: play sound
+		return BusyBeepingState
+
 class DialingState(AbstractState):
 	def __init__(self, controller):
 		super(DialingState, self).__init__(controller)
@@ -186,6 +194,8 @@ class StateMachineController(object):
 		self.__phone = phone
 		self.__feap = feap
 
+		self.__timeout = None
+
 		self.__running = True
 		self.__evqueue = queue.Queue()
 		self.__evthread = threading.Thread(target=self.__event_dispatcher)
@@ -210,27 +220,19 @@ class StateMachineController(object):
 			print('%s -> %s' % (oldstate.__name__, newstate.__name__))
 			self.__state = newstate(self)
 
-	def __timeout_thread(self, timeout):
-		i = 0
-		while self.__do_timeout and self.__running:
-			time.sleep(0.001)
-			i += 1
-			if i == timeout and self.__do_timeout:
-				self.queue_event('timeout')
-				return
-	
 	def queue_event(self, evname, *evargs, **evkwargs):
 		if not hasattr(AbstractState, 'on_%s' % (evname)):
 			raise ValueError('Illegal event name: %s' % (evname))
 		self.__evqueue.put((evname, evargs, evkwargs))
 
 	def set_timeout(self, timeout):
-		self.__do_timeout = True
-		t = threading.Thread(target=self.__timeout_thread, args=(timeout,))
-		t.start()
+		self.__timeout = threading.Timer(timeout/1000, lambda: self.queue_event('timeout'))
+		self.__timeout.start()
 
 	def abort_timeout(self):
-		self.__do_timeout = False
+		if self.__timeout:
+			self.__timeout.cancel()
+		self.__timeout = None
 
 	def get_phone(self):
 		return phone
@@ -243,7 +245,6 @@ class StateMachineController(object):
 			self.__running = False
 		self.__evqueue.put((None, None, None))
 
-
 c = None
 def gabelschalter_cb(state):
 	global c
@@ -269,6 +270,8 @@ def phone_cb(event):
 		c.queue_event('call_ended')
 	elif event == PhoneEvent.CallRinging:
 		c.queue_event('call_ringing')
+	elif event == PhoneEvent.CallInvalidNumber:
+		c.queue_event('invalid_number')
 
 if __name__ == '__main__':
 	phone = PhoneInterface(None, '.linphonerc')
diff --git a/phoneinterface.py b/phoneinterface.py
index 92b4829..960b72f 100644
--- a/phoneinterface.py
+++ b/phoneinterface.py
@@ -15,7 +15,8 @@ class PhoneEvent(object):
     CallRinging,\
     CallAccepted,\
     CallEnded,\
-    CallBusy= range(7)
+    CallBusy,\
+    CallInvalidNumber = range(8)
 
     @classmethod
     def string(cls, val):
@@ -76,8 +77,13 @@ class PhoneInterface(object):
         elif state == linphone.CallState.End:
             evt = PhoneEvent.CallEnded
         elif state == linphone.CallState.Error:
-            if call.error_info.reason == linphone.Reason.Busy:
+            error = call.error_info.reason
+            if error == linphone.Reason.Busy:
                 evt = PhoneEvent.CallBusy
+            elif error == linphone.Reason.NotFound:
+                evt = PhoneEvent.CallInvalidNumber
+            else:
+                evt = PhoneEvent.CallEnded
 
         if evt is not None:
             for cb in self.__event_cbs: