diff --git a/rtxHelpers.py b/rtxHelpers.py
index 6fdd903..89b5453 100644
--- a/rtxHelpers.py
+++ b/rtxHelpers.py
@@ -13,151 +13,151 @@ import logging
 import config
 
 def process_byte(in_byte):
-	""" takes the received byte and processes the command line
-	if a new command has been entered, it will call process_command()
-	if a short link has been entered, the link_list of the current page will be searched
-	and the found target will be sent to process_command()
-	"""
-	instr=str(in_byte, encoding="latin-1")
-	
-	if config.MODE=="modem":
-		logging.debug("> %s < CD: %s", instr, glob.ser.getCD())
+    """ takes the received byte and processes the command line
+    if a new command has been entered, it will call process_command()
+    if a short link has been entered, the link_list of the current page will be searched
+    and the found target will be sent to process_command()
+    """
+    instr=str(in_byte, encoding="latin-1")
+    
+    if config.MODE=="modem":
+        logging.debug("> %s < CD: %s", instr, glob.ser.getCD())
 
-	# what to send back to the client
-	if instr == cept.INI:
-		logging.debug("INI")
-		echo_char = "*"
-	elif instr == cept.TER:
-		logging.debug("TER")
-		echo_char = "#"
-	else:
-		echo_char=instr
+    # what to send back to the client
+    if instr == cept.INI:
+        logging.debug("INI")
+        echo_char = "*"
+    elif instr == cept.TER:
+        logging.debug("TER")
+        echo_char = "#"
+    else:
+        echo_char=instr
 
-	# start of line: clear rest of cmdline
-	if len(glob.cmdline) == 0:
-		glob.ser.write(bytes(cept.CLEARLINE, "latin-1"))
+    # start of line: clear rest of cmdline
+    if len(glob.cmdline) == 0:
+        glob.ser.write(bytes(cept.CLEARLINE, "latin-1"))
 
-	# echo the character to the client
-	glob.ser.write(bytes(echo_char, "latin-1"))
+    # echo the character to the client
+    glob.ser.write(bytes(echo_char, "latin-1"))
 
-	glob.cmdline += instr
+    glob.cmdline += instr
 
-	# Backspace:
-	if instr == cept.BSP:
-		glob.cmdline = glob.cmdline[:-1]
-		return
+    # Backspace:
+    if instr == cept.BSP:
+        glob.cmdline = glob.cmdline[:-1]
+        return
 
-	logging.debug("Cmdline: >%s<", glob.cmdline)
+    logging.debug("Cmdline: >%s<", glob.cmdline)
 
-	# process links inside the page:
-	if ( len(glob.cmdline) == 1 or len(glob.cmdline) == 2 ) and glob.curpage.get_link(glob.cmdline):
-		glob.cmdline = cept.INI + glob.curpage.get_link(glob.cmdline) + cept.TER
-		process_command(glob.cmdline)
-		return
+    # process links inside the page:
+    if ( len(glob.cmdline) == 1 or len(glob.cmdline) == 2 ) and glob.curpage.get_link(glob.cmdline):
+        glob.cmdline = cept.INI + glob.curpage.get_link(glob.cmdline) + cept.TER
+        process_command(glob.cmdline)
+        return
 
-	# reset cmdline:
-	if instr == cept.INI and glob.cmdline[-2:] == cept.INI+cept.INI:
-		logging.debug("reset cmdline")
-		glob.cmdline = ""
-		glob.ser.write(bytes(cept.clear_line24, "latin-1"))
-		return
+    # reset cmdline:
+    if instr == cept.INI and glob.cmdline[-2:] == cept.INI+cept.INI:
+        logging.debug("reset cmdline")
+        glob.cmdline = ""
+        glob.ser.write(bytes(cept.clear_line24, "latin-1"))
+        return
 
-	# goto last page:
-	if instr == cept.TER and glob.cmdline == cept.INI+cept.TER:
-		if glob.prevpage.get_page_id() == -1:
-			glob.cmdline = ""
-			send_error("Keine vorige Seite vorhanden.")
-			return
-		glob.cmdline = "" # reset cmdline
-		goto_last_page()
-		return
+    # goto last page:
+    if instr == cept.TER and glob.cmdline == cept.INI+cept.TER:
+        if glob.prevpage.get_page_id() == -1:
+            glob.cmdline = ""
+            send_error("Keine vorige Seite vorhanden.")
+            return
+        glob.cmdline = "" # reset cmdline
+        goto_last_page()
+        return
 
-	# "Make it so":
-	if instr == cept.TER:
-		# or instr == cept.SEND or instr == cept.CR:
-		logging.info("Kommando: >%s<", glob.cmdline)
-		process_command(glob.cmdline)
-		return
+    # "Make it so":
+    if instr == cept.TER:
+        # or instr == cept.SEND or instr == cept.CR:
+        logging.info("Kommando: >%s<", glob.cmdline)
+        process_command(glob.cmdline)
+        return
 
 def process_command(cmd):
-	""" processes the given command line
-	"""
+    """ processes the given command line
+    """
 
-	# reset cmdline
-	glob.cmdline = ""
+    # reset cmdline
+    glob.cmdline = ""
 
-	# process *cmdline#, normally a page-loading command:
-	if cmd[0] == cept.INI and cmd[-1:] == cept.TER:
-		pgnr = cmd[1:-1]
-		check_and_send_page(pgnr, "Die Seite kann nicht gefunden werden.")
+    # process *cmdline#, normally a page-loading command:
+    if cmd[0] == cept.INI and cmd[-1:] == cept.TER:
+        pgnr = cmd[1:-1]
+        check_and_send_page(pgnr, "Die Seite kann nicht gefunden werden.")
 
-	# if only # is entered, either go to the link behind '#'
-	# or to the next sub-page (2000a => 2000b) if it exists
-	if cmd == cept.TER:
-		if glob.curpage.get_link("#"):
-			pgnr = glob.curpage.get_link("#")
-			check_and_send_page(pgnr, "Die Seite kann nicht gefunden werden.")
-		else:
-			# check if the next page exists, e.g. 2000a => 2000b
-			curid = glob.curpage.get_page_id()
-			if curid[-1:].isalpha():
-				# aus 2000a 2000b machen:
-				nextid = curid[:-1] + chr(ord(curid[-1:])+1)
-				check_and_send_page(nextid, "Keine n"+str(cept['UMLAUT'])+"achste Seite gefunden.")
+    # if only # is entered, either go to the link behind '#'
+    # or to the next sub-page (2000a => 2000b) if it exists
+    if cmd == cept.TER:
+        if glob.curpage.get_link("#"):
+            pgnr = glob.curpage.get_link("#")
+            check_and_send_page(pgnr, "Die Seite kann nicht gefunden werden.")
+        else:
+            # check if the next page exists, e.g. 2000a => 2000b
+            curid = glob.curpage.get_page_id()
+            if curid[-1:].isalpha():
+                # aus 2000a 2000b machen:
+                nextid = curid[:-1] + chr(ord(curid[-1:])+1)
+                check_and_send_page(nextid, "Keine n"+str(cept['UMLAUT'])+"achste Seite gefunden.")
 
-	# special commands:
-	if cmd == "!1" + cept.TER:
-		send_welcome_page()
-		return
-	if cmd == "!2" + cept.TER:
-		glob.ser.write(bytes(cept.init_screen, "latin-1"))
-		return
+    # special commands:
+    if cmd == "!1" + cept.TER:
+        send_welcome_page()
+        return
+    if cmd == "!2" + cept.TER:
+        glob.ser.write(bytes(cept.init_screen, "latin-1"))
+        return
 
 def goto_last_page():
-	""" go back to the previous page and make the current page the previous page
-	"""
-	logging.info("Letzte Seite: %s", str(glob.prevpage.get_page_id()))
+    """ go back to the previous page and make the current page the previous page
+    """
+    logging.info("Letzte Seite: %s", str(glob.prevpage.get_page_id()))
 
-	# swap prevpage and curpage
-	temp = glob.curpage
-	glob.curpage = glob.prevpage
-	glob.prevpage = temp
+    # swap prevpage and curpage
+    temp = glob.curpage
+    glob.curpage = glob.prevpage
+    glob.prevpage = temp
 
-	# send the previous page (now curpage) to the client
-	send_page(glob.curpage)
+    # send the previous page (now curpage) to the client
+    send_page(glob.curpage)
 
 def send_welcome_page():
-	""" get the btxlogo, make a rtxPage of it and send it to the client """
-	wpage = rtxPage()
-	wpage.set_page(bytes(cept.btxlogo, "latin-1"))
-	send_page(wpage)
+    """ get the btxlogo, make a rtxPage of it and send it to the client """
+    wpage = rtxPage()
+    wpage.set_page(bytes(cept.btxlogo, "latin-1"))
+    send_page(wpage)
 
 def check_and_send_page(pgnr, errormsg):
-	""" checks if the page "pgnr" exists
-	if yes, it loads it into curpage and sends it to the client
-	if not, it sends the error message "errormsg" to the client
-	"""
-	logging.info("suche Seite: >%s<", pgnr)
+    """ checks if the page "pgnr" exists
+    if yes, it loads it into curpage and sends it to the client
+    if not, it sends the error message "errormsg" to the client
+    """
+    logging.info("suche Seite: >%s<", pgnr)
 
-	if rtxPage.exists(pgnr):
-		glob.prevpage = glob.curpage
-		glob.curpage = rtxPage(pgnr)
-		send_page(glob.curpage) # takes a rtxPage object!
-		return True
-	elif pgnr[-1:].isnumeric() and rtxPage.exists(pgnr + "a"):
-		glob.prevpage = glob.curpage
-		glob.curpage = rtxPage(pgnr + "a")
-		send_page(glob.curpage) # takes a rtxPage object!
-		return True
-	else:
-		send_error(errormsg)
-		return False
+    if rtxPage.exists(pgnr):
+        glob.prevpage = glob.curpage
+        glob.curpage = rtxPage(pgnr)
+        send_page(glob.curpage) # takes a rtxPage object!
+        return True
+    elif pgnr[-1:].isnumeric() and rtxPage.exists(pgnr + "a"):
+        glob.prevpage = glob.curpage
+        glob.curpage = rtxPage(pgnr + "a")
+        send_page(glob.curpage) # takes a rtxPage object!
+        return True
+    else:
+        send_error(errormsg)
+        return False
 
 def send_error(msg):
-	""" send an error message to the client """
-	glob.ser.write(bytes(cept.error_prefix + msg + cept.error_suffix, "latin-1"))
+    """ send an error message to the client """
+    glob.ser.write(bytes(cept.error_prefix + msg + cept.error_suffix, "latin-1"))
 
 def send_page(page):
-	""" sends a page to the client """
-	glob.ser.write(page.get_page())
+    """ sends a page to the client """
+    glob.ser.write(page.get_page())
 
diff --git a/rtxModem.py b/rtxModem.py
index 64125b7..0aa1b0c 100644
--- a/rtxModem.py
+++ b/rtxModem.py
@@ -12,51 +12,51 @@ import config
 import logging
 
 def init_modem():
-	logging.debug("clearing input/output buffers")
-	glob.ser.reset_input_buffer()
-	glob.ser.reset_output_buffer()
-	""" send the modem init strings to the modem """
-	logging.debug("init_modem")
-	if config.MODEM_INIT1 != "":
-		logging.debug("sending MODEM_INIT1")
-		glob.ser.write(bytes(config.MODEM_INIT1 + "\r", "latin-1"))
-		rc = _serial_readline()
-		logging.info("MODEM_INIT1: %s", rc)
-		rc = _serial_readline()
-		logging.info("MODEM_INIT1: %s", rc)
+    logging.debug("clearing input/output buffers")
+    glob.ser.reset_input_buffer()
+    glob.ser.reset_output_buffer()
+    """ send the modem init strings to the modem """
+    logging.debug("init_modem")
+    if config.MODEM_INIT1 != "":
+        logging.debug("sending MODEM_INIT1")
+        glob.ser.write(bytes(config.MODEM_INIT1 + "\r", "latin-1"))
+        rc = _serial_readline()
+        logging.info("MODEM_INIT1: %s", rc)
+        rc = _serial_readline()
+        logging.info("MODEM_INIT1: %s", rc)
 
-	if config.MODEM_INIT2 != "":
-		logging.debug("sending MODEM_INIT2")
-		glob.ser.write(bytes(config.MODEM_INIT2 + "\r", "latin-1"))
-		rc = _serial_readline()
-		logging.info("MODEM_INIT2: %s", rc)
-		rc = _serial_readline()
-		logging.info("MODEM_INIT2: %s", rc)
+    if config.MODEM_INIT2 != "":
+        logging.debug("sending MODEM_INIT2")
+        glob.ser.write(bytes(config.MODEM_INIT2 + "\r", "latin-1"))
+        rc = _serial_readline()
+        logging.info("MODEM_INIT2: %s", rc)
+        rc = _serial_readline()
+        logging.info("MODEM_INIT2: %s", rc)
 
 def wait_for_caller():
-	""" waits for the RING of the modem and answers it """
-	modem_answered = False
-	logging.debug("wait_for_caller")
-	while not modem_answered:
-		rc = _serial_readline()
-		if rc.startswith(config.MODEM_RING):
-			logging.info("modem ringing! Answering.")
-			glob.ser.write(bytes(config.MODEM_ANSWER + "\r", "latin-1"))
-			rc = _serial_readline()
-			logging.info("Answer: %s", rc)
-			rc = _serial_readline()
-			logging.info("Answer: %s", rc)
-			modem_answered=True
-		else:
-			modem_answered=False
+    """ waits for the RING of the modem and answers it """
+    modem_answered = False
+    logging.debug("wait_for_caller")
+    while not modem_answered:
+        rc = _serial_readline()
+        if rc.startswith(config.MODEM_RING):
+            logging.info("modem ringing! Answering.")
+            glob.ser.write(bytes(config.MODEM_ANSWER + "\r", "latin-1"))
+            rc = _serial_readline()
+            logging.info("Answer: %s", rc)
+            rc = _serial_readline()
+            logging.info("Answer: %s", rc)
+            modem_answered=True
+        else:
+            modem_answered=False
 
 def _serial_readline():
-	line = ""
-	in_byte = ""
-	
-	while not in_byte == b"\n":
-		in_byte = glob.ser.read(1)
-		#print(in_byte)
-		line += str(in_byte, encoding="latin-1")
+    line = ""
+    in_byte = ""
+    
+    while not in_byte == b"\n":
+        in_byte = glob.ser.read(1)
+        #print(in_byte)
+        line += str(in_byte, encoding="latin-1")
 
-	return line
+    return line
diff --git a/rtxPage.py b/rtxPage.py
index 078f76e..599780a 100644
--- a/rtxPage.py
+++ b/rtxPage.py
@@ -12,103 +12,103 @@ import config
 import logging
 
 class rtxPage:
-	""" Klasse zur Benutzung einer CEPT-Seite
-	"""
+    """ Klasse zur Benutzung einer CEPT-Seite
+    """
 
-	die_seite = ""
-	seiten_nummer = -1
-	link_liste = {}
+    die_seite = ""
+    seiten_nummer = -1
+    link_liste = {}
 
-	def __init__(self, page = None):
-		""" create a new page object for the page 'page' 
-		returns False if the page cannot be found
-		returns True if the page has been loaded
-		"""
-		if page == None:
-			return
-		else:
-			self.die_seite = ""
-			self.seiten_nummer = -1
-			self.link_liste = {}
-			self._load_page(page)
+    def __init__(self, page = None):
+        """ create a new page object for the page 'page' 
+        returns False if the page cannot be found
+        returns True if the page has been loaded
+        """
+        if page == None:
+            return
+        else:
+            self.die_seite = ""
+            self.seiten_nummer = -1
+            self.link_liste = {}
+            self._load_page(page)
 
-	@staticmethod
-	def exists(page):
-		""" checks if the page (i.e. the file) exists """
-		if os.path.isfile(config.PAGES + page):
-			return True
-		elif os.path.isfile(config.DEMOPAGES + page):
-			return True
-		else:
-			return False
+    @staticmethod
+    def exists(page):
+        """ checks if the page (i.e. the file) exists """
+        if os.path.isfile(config.PAGES + page):
+            return True
+        elif os.path.isfile(config.DEMOPAGES + page):
+            return True
+        else:
+            return False
 
-	def get_page(self):
-		""" returns the page if loaded 
-		returns False if no page has been loaded
-		"""
-		if self.die_seite != "":
-			return self.die_seite
-		else:
-			return False
+    def get_page(self):
+        """ returns the page if loaded 
+        returns False if no page has been loaded
+        """
+        if self.die_seite != "":
+            return self.die_seite
+        else:
+            return False
 
-	def set_page(self,pagedata):
-		""" write the pagedata as the new page and (probably) the link list """
-		self.die_seite = pagedata
-		self.link_liste = self._get_link_list()
+    def set_page(self,pagedata):
+        """ write the pagedata as the new page and (probably) the link list """
+        self.die_seite = pagedata
+        self.link_liste = self._get_link_list()
 
-	def get_links(self):
-		""" returns the list of links found in this page """
-		return self.link_liste
+    def get_links(self):
+        """ returns the list of links found in this page """
+        return self.link_liste
 
-	def get_link(self, link):
-		""" returns the target for a given link
-		returns False if this link does not exist 
-		"""
-		if link in self.link_liste:
-			return self.link_liste[link]
-		else:
-			return False
+    def get_link(self, link):
+        """ returns the target for a given link
+        returns False if this link does not exist 
+        """
+        if link in self.link_liste:
+            return self.link_liste[link]
+        else:
+            return False
 
-	def get_page_id(self):
-		""" returns the id of the current page """
-		return self.seiten_nummer
+    def get_page_id(self):
+        """ returns the id of the current page """
+        return self.seiten_nummer
 
-	def _load_page(self, page):
-		""" Load a CEPT page from the file system 
-		returns False if the page cannot be found
-		returns True if the page has been loaded
-		"""
-		if os.path.isfile(config.PAGES + page):
-			filename = config.PAGES + page
-		elif os.path.isfile(config.DEMOPAGES + page):
-			filename = config.DEMOPAGES + page
-		else:
-			return False
-		
-		with open(filename, "rb") as f:
-			self.die_seite = f.read()
-		self.seiten_nummer = page
-		link_liste = self._get_link_list()
-		return True
+    def _load_page(self, page):
+        """ Load a CEPT page from the file system 
+        returns False if the page cannot be found
+        returns True if the page has been loaded
+        """
+        if os.path.isfile(config.PAGES + page):
+            filename = config.PAGES + page
+        elif os.path.isfile(config.DEMOPAGES + page):
+            filename = config.DEMOPAGES + page
+        else:
+            return False
+        
+        with open(filename, "rb") as f:
+            self.die_seite = f.read()
+        self.seiten_nummer = page
+        link_liste = self._get_link_list()
+        return True
 
-	def _get_link_list(self):
-		""" private function which parses the CEPT page and extracts the link list
-		returns True if links have been found
-		returns False if no links have been found
-		"""
-		links = []
-		links = re.findall("\x1f\x3d([^\x1f\x9b\x1b]+)", str(self.die_seite, "latin-1"))
+    def _get_link_list(self):
+        """ private function which parses the CEPT page and extracts the link list
+        returns True if links have been found
+        returns False if no links have been found
+        """
+        links = []
+        links = re.findall("\x1f\x3d([^\x1f\x9b\x1b]+)", str(self.die_seite, "latin-1"))
 
-		for item in links:
-			if item[0] != "0":
-				link = item[1:3].strip()
-				target = item[3:].strip()
-				self.link_liste[link] = target
+        for item in links:
+            if item[0] != "0":
+                link = item[1:3].strip()
+                target = item[3:].strip()
+                self.link_liste[link] = target
 
-		logging.info(self.link_liste)
+        logging.info(self.link_liste)
 
-		if self.link_liste == {}:
-			return False
-		else:
-			return True
+        if self.link_liste == {}:
+            return False
+        else:
+            return True