diff --git a/client-barcode/display.py b/client-barcode/display.py
index 59ad56d..b1459e3 100644
--- a/client-barcode/display.py
+++ b/client-barcode/display.py
@@ -1,36 +1,70 @@
 import serial
-
-
+from thread import start_new_thread, allocate_lock
+import time
 
 class Display:
 	def __init__(self,portname="/dev/ttyUSB0"):
 		self.serialport=None
-		self.open_port(portname)
+		self.portlock = allocate_lock()
+		self.portname=portname
+		self.open_port()
+		self.brightness=0
+		self.screensaver = Screensaver(self)
+		self.screensaver.start()
 
 	def __del__(self):
+		if (not self.screensaver == None):
+			self.screensaver.terminate()
+			self.screensaver = None
+
 		if (not self.serialport == None):
 			self.serialport.close()
 			self.serialport=None
 
-	def open_port(self,portname):
-		self.serialport = serial.Serial(portname,9600,timeout=2,rtscts=True, dsrdtr=True)
-		print ("Initializing display:\n  %s\n" % self.serialport )
-		self.cmd_reset()
-		self.write("Hello world")
+	def open_port(self):
+
+		self.mutex_get()
+		try:
+			self.serialport = serial.Serial(self.portname,9600,timeout=2,rtscts=True, dsrdtr=True)
+			print ("Initializing display on port:\n  %s\n" % self.serialport )
+			self.cmd_reset()
+			self.mutex_release()
+		except Exception as e:
+			print ("Exception opening serial port '%s' for display\n" % self.portname)
+			print ("Ignoring and trying to open it again later\n")
+			print (e)
+			self.serialport = None
+			self.mutex_release()
+			pass
+		
+
+
 
 	def cmd_reset(self):
 		#reset the display
-		self.write("\x1b\x40")
+		self.cmd("\x1b\x40")
 
 	def cmd_cursor_show(self,on=True):
 		#show or hide the cursor
 		if (on): 
-			self.write("\x1f\x43\x01")
+			self.cmd("\x1f\x43\x01")
 		else:
-			self.write("\x1f\x43\x00")
+			self.cmd("\x1f\x43\x00")
 
 	def cmd_blink(self,rate=127):
-		self.write("\x1f\x45%c" % rate)
+		self.cmd("\x1f\x45%c" % chr(rate))
+
+
+	def cmd_brightness(self,level):
+		if (level==0): #turn off:
+			self.cmd_display_on(False)	
+                        self.brightness = level
+                        return
+		else:  
+			if (self.brightness==0): #turn on, then set wanted brightness:
+				self.cmd_display_on(True)	
+                        self.brightness = level
+                        self.cmd("\x1F\x58%c" % chr(level-1) )
 
 	def cmd_display_on(self,on=True):
 		# blink-command: 
@@ -51,24 +85,105 @@ class Display:
 		cmd_curmode(3)			
 
 	def cmd_curmode(self,val=2):
-		self.write("\x1f%c" % val)
+		self.cmd("\x1f%c" % chr(val))
 
 	def cmd_clear(self):
-		self.write("\x0c")
+		self.cmd("\x0c")
 
 	
 	def cmd_time(self):
 		# activate timer display in lower right corner.
 		# actual time has to be set via display_set_timer.
-		self.write("\x1f\x55")
+		self.cmd("\x1f\x55")
 
-	def cmd_time_set(self,h,m):
+	def cmd_time_set(self,h=None,m=None):
+		if (h==None or m==None):
+			now = time.localtime()
+			h=now.tm_hour
+			m=now.tm_min
 		# configures hour and minutes of the internal clock and
 		# displays the time in the lower right corner.
 		# turns off when something gets written into the line.
 		# two bytes have to follow with hour and minute
-		self.write("\x1F\x54%c%c" % (h,m) )
+		self.cmd("\x1F\x54%c%c" % (chr(h),chr(m)) )
+		self.cmd_curmode_hscroll() # makes the time more robust...
+
+	def cmd(self,text): #for commands: do not reset screensaver timeout
+		self.write(text,False)
 
+	def write(self,text,idle_reset=True): #for data: reset screensaver timeout
+		if (not self.serialport == None):
+			if (idle_reset):
+				self.screensaver.idle_reset();
+			self.serialport.write(text)	
+		else:
+			self.open_port()	
+
+
+	def mutex_get(self):
+		self.portlock.acquire()
+
+	def mutex_release(self):
+		self.portlock.release()
+
+	def terminate(self):
+		if (not self.screensaver == None):
+			self.screensaver.terminate()
+			self.screensaver = None
+		
+
+import threading
+import time
+
+class Screensaver (threading.Thread):
+	def __init__(self,display):
+		self.display=display
+		self.runme=True
+		self.idlecounter=0
+		self.timeout_dim=30
+		self.timeout_message=60
+		self.timeout_off=120
+		self.mutex = allocate_lock()
+	        threading.Thread.__init__(self)
+
+	def run(self):
+		print "Starting Screensaver thread" 
+		while(self.runme):
+			self.mutex.acquire()
+			self._main_loop()
+			self.mutex.release()
+			time.sleep(.5)
+		print "Exiting Screensaver thread"
+
+	def terminate(self):
+		self.runme = False
+
+
+	def idle_reset(self):
+		self.mutex.acquire()
+		self.idlecounter=0
+		self.mutex.release()
+
+	def _main_loop(self):
+		if (self.idlecounter < self.timeout_off):
+			self.idlecounter+=1
+
+		if (self.idlecounter>=self.timeout_dim and self.idlecounter <= (self.timeout_dim+7)):
+			x = (8-( self.idlecounter - self.timeout_dim))/2
+			self.display.mutax_get()
+			self.display.cmd_brightness(1+x)
+			self.display.mutax_release()
+			return
+
+		if (self.idlecounter==self.timeout_message):
+			return
+
+		if (self.idlecounter==self.timeout_off):
+			self.display.mutax_get()
+                        display.cmd_display_on(False)
+			self.display.mutax_release()
+			return
+		
+	def __del__(self):
+		print("bye")
 
-	def write(self,text):
-		self.serialport.write(text)	
diff --git a/client-barcode/freitagskasse.py b/client-barcode/freitagskasse.py
index d8ce0ba..c8214ff 100644
--- a/client-barcode/freitagskasse.py
+++ b/client-barcode/freitagskasse.py
@@ -60,6 +60,7 @@ lock = allocate_lock()
 def display_scroll_text(line,text):
 	global scroll_line1,scroll_line2
 	global offset_line1,offset_line2
+	global lock
 	lock.acquire()
 	if (line==1): #clear the line on invocation:
 		send_display("\x1f\x24\x01%c\x18" % chr(line) )
@@ -91,18 +92,7 @@ def display_handle_scroll(line,text,offset):
 
 
 def display_cmd_dim(x):
-	global brightness
-	if (brightness!=x):
-		if (x==0): #turn off:
-			send_display("\x1F\x45%c" % chr(255) )
-			brightness = x
-			return
-			
-		else:
-			if (brightness==0): #turn on, then set wanted brightness:
-				send_display("\x1F\x45%c" % chr(0) )
-			brightness = x
-			send_display("\x1F\x58%c" % chr(x-1) )
+	return
 
 
 def display_thread(x):
@@ -110,6 +100,7 @@ def display_thread(x):
 	global offset_line1,offset_line2
 	global screensaver
 	global idlemessage
+	global lock
 
 	offset_line1=0
 	offset_line2=0
@@ -122,9 +113,6 @@ def display_thread(x):
 		if (screensaver <= SCREENSAVER_OFF):
 			screensaver=screensaver+1
 
-		if ((screensaver >= SCREENSAVER_DIM) and (screensaver <= (SCREENSAVER_DIM+7))): #activate first stage of screensaver:
-			x = (8-( screensaver - SCREENSAVER_DIM))/2
-			display_cmd_dim(1+x)
 
 		if (screensaver == SCREENSAVER_TIMEOUT):
 			now = time.localtime()
@@ -136,36 +124,14 @@ def display_thread(x):
 			scroll_line2=None
 			offset_line1=0
 			offset_line2=0				
-		
-		if (screensaver == SCREENSAVER_OFF):
-			display_cmd_dim(0)
 			
 		lock.release()
 		time.sleep(.5)
 
 
 def send_display(s):
-	global display_fifo
-	if not display_fifo:
-		try:
-			fd = os.open( "/tmp/display", os.O_WRONLY)
-			display_fifo = os.fdopen(fd,"w")
-		except OSError:
-			display_fifo = None
-			pass
-			return
-		except IOError:
-			display_fifo = None
-			pass
-			return
-	try:
-		display_fifo.write(s)
-		display_fifo.flush()
-	except IOError:
-		display_fifo = None
-		pass
-		return
-
+	global myDisplay
+	myDisplay.write(s)
 
 #Front-End Funtion to display a Screen
 # with heading
@@ -198,6 +164,8 @@ def print_display(s):
 	global scroll_line1,scroll_line2
 	global offset_line1,offset_line2
 	global screensaver
+	global myDisplay
+	global lock
 
 	lock.acquire()
 	screensaver=0
@@ -206,7 +174,7 @@ def print_display(s):
 	scroll_line1=None
 	scroll_line2=None
 	display_cmd_dim(5)
-	send_display(s)
+	myDisplay.write(s)
 	lock.release()
 
 def clear():
@@ -582,8 +550,7 @@ def main():
 
 	myDisplay = Display("/dev/ttyUSB0")
 	myDisplay.cmd_reset()
-
-	print_display("\x1b\x40\x1f\x43\x00")
+	myDisplay.cmd_cursor_show(False)
 	start_new_thread(display_thread,(1,))
 
 	#display_scroll_text(1,"Line1: Text, dumm scrollend!")
@@ -605,3 +572,5 @@ if __name__ == '__main__':
 	except KeyboardInterrupt:
 		pass
 		print_display("\x1b\x40Goodbye!")
+		myDisplay.terminate()
+