diff --git a/configreader.py b/configreader.py
index 6a1657e..f0780fc 100644
--- a/configreader.py
+++ b/configreader.py
@@ -15,6 +15,7 @@ class ConfigurationReader(object):
 		'pin_wecker_enable': '16',
 		'pin_wecker_a': '18',
 		'pin_wecker_b': '19',
+		'invert_gs' : 'false',
 
 		'default_proxy': ''
 	}
@@ -35,6 +36,9 @@ class ConfigurationReader(object):
 	def __get_global_val_int(self, option):
 		return int(self.__cp.get('fetapd', option))
 
+	def __get_global_val_bool(self, option):
+		return self.__cp.get('fetapd', option).lower() in ['true', 'yes', '1']
+
 
 	def __get_proxy_val(self, proxyname, option):
 		return self.__cp.get('proxy_'+proxyname, option)
@@ -67,7 +71,8 @@ class ConfigurationReader(object):
 			pin_schauzeichen = self.__get_global_val_int('pin_schauzeichen'),
 			pin_wecker_enable = self.__get_global_val_int('pin_wecker_enable'),
 			pin_wecker_a = self.__get_global_val_int('pin_wecker_a'),
-			pin_wecker_b = self.__get_global_val_int('pin_wecker_b')
+			pin_wecker_b = self.__get_global_val_int('pin_wecker_b'),
+			invert_gs = self.__get_global_val_bool('invert_gs'),
 		)
 
 		self.__dialconfig = fetapdtest.DialConfiguration(
diff --git a/fetap.ini.example b/fetap.ini.example
index fc5f006..17a9dd7 100644
--- a/fetap.ini.example
+++ b/fetap.ini.example
@@ -10,6 +10,7 @@ pin_schauzeichen = 12
 pin_wecker_enable = 16
 pin_wecker_a = 18
 pin_wecker_b = 19
+invert_gs = false
 
 ; Zeit bevor ein eingehender Anruf automatisch abgewiesen wird
 incoming_timeout = 60
diff --git a/phoneinterface.py b/phoneinterface.py
index 2b19688..9582b2a 100644
--- a/phoneinterface.py
+++ b/phoneinterface.py
@@ -159,6 +159,7 @@ class PhoneInterface(object):
             # Try to resolve prefix
             for p in self.__config.proxies:
                 if number.startswith(p.prefix):
+                    number = number[len(p.prefix):]
                     number += '@' + p.realm
                     break
         self.__core.invite(number)
diff --git a/tuitest.py b/tuitest.py
index 250613c..4ed83ab 100644
--- a/tuitest.py
+++ b/tuitest.py
@@ -7,7 +7,7 @@ import threading
 class FeApPinConfiguration(object):
 	def __init__(self, gpio_numbering, pin_nsa, pin_nsi, pin_gabelschalter,
 	             pin_schauzeichen, pin_wecker_enable, pin_wecker_a,
-	             pin_wecker_b):
+	             pin_wecker_b, invert_gs):
 		if gpio_numbering == 'BOARD':
 			gpio_numbering = gpio.BOARD
 		elif gpio_numbering == 'BCM':
@@ -23,6 +23,7 @@ class FeApPinConfiguration(object):
 		self.pin_wecker_enable = pin_wecker_enable
 		self.pin_wecker_a = pin_wecker_a
 		self.pin_wecker_b = pin_wecker_b
+		self.invert_gs = invert_gs
 
 class FeApUserInterface(object):
 	def __init__(self, pinconfig):
@@ -69,6 +70,8 @@ class FeApUserInterface(object):
 	
 	def __on_gabelschalter_change(self, pin):
 		gbstate = gpio.input(self.__pinconfig.pin_gabelschalter)
+		if self.__pinconfig.invert_gs:
+			gbstate = 1 - gbstate
 		print 'gabelschalter:', gbstate
 		for cb in self.__gabelschalter_callbacks:
 			cb(gbstate)