diff --git a/rtxMask.py b/rtxMask.py
index 545cdd7..7a41b94 100644
--- a/rtxMask.py
+++ b/rtxMask.py
@@ -12,104 +12,141 @@ import config
 import cept
 
 class rtxMask:
-	""" Klasse zur Verarbeitung einer Eingabemaske
-	"""
+    """ Klasse zur Verarbeitung einer Eingabemaske
+    """
 
-	lines = []
-	answers = []
+    lines = []
+    answers = []
 
-	def __init__(self):
+    def __init__(self):
 
-	def addLine(x, y, length):
-		""" adds a new line for the mask to the object """
-		newLine['x'] = x
-		newLine['y'] = y
-		newLine['length'] = length
-		self.lines.append(newLine)
+    def addLine(x, y, length):
+        """ adds a new line for the mask to the object """
+        newLine['x'] = x
+        newLine['y'] = y
+        newLine['length'] = length
+        self.lines.append(newLine)
 
-	def get_answer(self, nr):
-		""" returns the answer for a specific line """
-		if nr >= 0 and nr <= len(self.answers):
-			return self.answers[nr]
-		else
-			return False
+    def get_answer(self, nr):
+        """ returns the answer for a specific line """
+        if nr >= 0 and nr <= len(self.answers):
+            return self.answers[nr]
+        else
+            return False
 
-	def get_answers(self):
-		""" returns the array of all answers """
-		return self.answers
+    def get_answers(self):
+        """ returns the array of all answers """
+        return self.answers
 
-	def _pos_cur_to_line(self, line):
-		""" positions the cursor to the beginning of a line """
-		zeile=self.lines[line]
-		self._pos_cur_to_xy(zeile['x'], zeile['y'])
+    def _pos_cur_to_line(self, line):
+        """ positions the cursor to the beginning of a line """
+        zeile=self.lines[line]
+        self._pos_cur_to_xy(zeile['x'], zeile['y'])
 
-	def _pos_cur_to_xy(self, x, y):
-		""" positions the cursor to a (x,y) position on screen """
-		toX=0x41 + x
-		toY=0x41 + y
-		gotoString = "\x1f" + chr(toX) + chr(toY)
-		glob.ser.write(bytes(gotoString, "latin-1"))
+    def _pos_cur_to_xy(self, x, y):
+        """ positions the cursor to a (x,y) position on screen """
+        toX=0x41 + x
+        toY=0x41 + y
+        gotoString = "\x1f" + chr(toX) + chr(toY)
+        glob.ser.write(bytes(gotoString, "latin-1"))
 
-	def _set_str_at_pos(self, char, pos, line):
-		""" changes the 'char' at a position 'pos' of a specific answer 'line' """
-		zeile = self.answers[line]
+    def _set_str_at_pos(self, char, pos, line):
+        """ changes the 'char' at a position 'pos' of a specific answer 'line' """
+        zeile = self.answers[line]
 
-		# if the line is shorter than the position, add spaces
-		while len(zeile) < pos:
-			zeile += " "
+        # if the line is shorter than the position, add spaces
+        while len(zeile) < pos:
+            zeile += " "
 
-		zeile = zeile[:pos-1] + char + zeile[pos:]
-		answers[line] = zeile
+        zeile = zeile[:pos-1] + char + zeile[pos:]
+        answers[line] = zeile
+"""
+    def _cut_off_rest_of_line(self, line, pos):
+        """ erases the rest of the line from the 'lines' variable and from the screen """
+        zeile = self.answers[line]
+        self.answers[line] = zeile[:pos]
 
-	def _cut_off_rest_of_line(self, line, pos):
-		""" erases the rest of the line from the 'lines' variable and from the screen """
-		zeile = self.answers[line]
-		self.answers[line] = zeile[:pos]
+        if zeile[pos:] != "":
+            numOfSpaces = len(zeile[pos:])
+            spaces = " " * numOfSpaces
+            backSpaces = cept.BSP * numOfSpaces
+            glob.ser.write(bytes(spaces + backSpaces, "latin-1"))
+"""
+    def process_input(self):
+        """ reads the input from the client, fills the mask and gets the input """
 
-		if zeile[pos:] != "":
-			numOfSpaces = len(zeile[pos:])
-			spaces = " " * numOfSpaces
-			backSpaces = "\x08" * numOfSpaces
-			glob.ser.write(bytes(spaces + backSpaces, "latin-1"))
+        # if there have no input lines been defined, no input can be processed - so exit the function
+        if len(lines) == 0:
+            logging.debug("Keine Zeilen in der Maske definiert!")
+            return False
 
-	def process_input(self):
-		""" reads the input from the client, fills the mask and gets the input """
+        # position the cursor into the first field
+        self._pos_cur_to_line(lines[0])
 
-		if len(lines) == 0:
-			logging.debug("Keine Zeilen in der Maske definiert!")
-			return False
+        posx = 0  # cursor position inside the line - max. position is length-1
+        posy = 0  # the current line - max. number is len(lines)-1
 
-		# position the cursor into the first field
-		self._pos_cur_to_line(lines[1])
-		posx = 0  # cursor position inside the line - max. position is length-1
-		posy = 0  # the current line - max. number is len(lines)-1
+        weiter = True
+        # read input and interpret it           
+        while weiter==True:
+            # if the modem hangs up, exit the function:
+            #if config.MODE == "modem" and glob.ser.getCD() == False:
+            #   weiter=False
+            in_byte = glob.ser.read(1)
+            instr = str(in_byte, encoding="latin-1")
+            echostr = instr
 
-		weiter = True
-		# read input and interpret it			
-		while weiter==True:
-			# if the modem hangs up, exit the function:
-			#if config.MODE == "modem" and glob.ser.getCD() == False:
-			#	weiter=False
-			in_byte = glob.ser.read(1)
-			instr = str(in_byte, encoding="latin-1")
-			echostr = instr
+            if instr == cept.TER or instr == cept.CR:
+                # go to the beginning of the next line
+                # or finish the mask
+                if posy == len(lines)-1:
+                    # this was the last line, now send the data
+                    # TODO: weitermachen
+                else:
+                    # go to the beginning of the next line
+                    posy += 1
+                    posx = 0
+                    self._pos_cur_to_line(lines[posy])
+            elif instr == cept.BSP:
+                answers[posy] = answers[posy][:-1]
+                posx -= 1
+            elif instr == cept.UP:
+                # if the cursor is in the first line, we can't go higher...
+                # so we ignore the keypress
+                echostr = "" # no echo needed, we position the curser ourselves
+                if posy > 0:
+                    posy -= 1
+                    posx = 0
+                    self._pos_cur_to_line(lines[posy])
+            elif instr == cept.DOWN:
+                # same here: last line => it can't go lower => ignore
+                echostr = "" # no echo needed, we position the curser ourselves
+                if posy < len(self.lines):
+                    posy += 1
+                    posx = 0
+                    self._pos_cur_to_line(lines[posy])
+            elif instr == cept.LEFT:
+                if posx > 0:
+                    posx -= 1
+                else:
+                    echostr = ""
+            elif instr == cept.RIGHT:
+                if posx < len(answers[posy]):
+                    posx += 1
+                else:
+                    echostr = ""
+            elif instr == cept.SEND:  # ist das DCT??
+                # TODO: send data               
+            elif instr.isalnum():
+                # "normal" input
+                # TODO: lineinput == Zeilenende beachten
+                self._set_str_at_pos(instr, posx, posy)
+                posx += 1
+            else:
+                # ignore the rest and do not echo it :)
+                echostr = ""
 
-			if instr == cept.TER or instr == cept.CR:
-				if posy == len(lines)-1:
-					# this was the last line, now send the data
-					# TODO
-					weiter = False
-			elif instr.isalnum():
-				self._set_str_at_pos(instr, posx, posy)
-				posx += 1
-			elif instr == cept.BSP:
-				answers[posy] = answers[posy][:-1]
-				posx -= 1
-			else:
-				echostr = ""
-
-			# lineinput == Zeilenende beachten
-
-			glob.ser.write(bytes(echostr, "latin-1"))
+            # now send the echo
+            glob.ser.write(bytes(echostr, "latin-1"))