diff --git a/interface_handler.py b/interface_handler.py
index 8b6226b..6c3e014 100644
--- a/interface_handler.py
+++ b/interface_handler.py
@@ -5,6 +5,8 @@ import sys
 sys.path.append('/home/pi/aped_device')
 
 from xml_reader import Xml_reader
+from ring_buffer import Ring_buffer
+
 class Interface_handler:
     """handles the access to the various interfaces (e.g. GPIO)
     """
@@ -51,7 +53,9 @@ class Interface_handler:
         self.xml_reader = xml_reader
         self.pwms = [None] * 41
         self.pwm_dutycycles = [None] * 41
+        self.buffers = [None] * 41
         self.init_gpio()
+        self.init_buffer()
 
 
     def init_gpio(self):
@@ -79,6 +83,15 @@ class Interface_handler:
                     self.pwms[self.Pin[pin].value] = pwm
                 else:
                     raise NotImplementedError('the protocol of the device %s is not implemented' % device_name)
+
+    def init_buffer(self):
+        for device_name in self.xml_reader.get_device_names():
+            port_info = self.xml_reader.get_port(device_name)
+            pins = port_info["pins"]
+            buffer_size = self.xml_reader.get_buffer_size(device_name)
+            if buffer_size != 0:
+                for pin in pins:
+                    self.buffers[self.Pin[pin].value] = Ring_buffer(buffer_size)
                 
 
     def read(self, device_name:str) -> dict:
diff --git a/ring_buffer.py b/ring_buffer.py
new file mode 100644
index 0000000..40ca564
--- /dev/null
+++ b/ring_buffer.py
@@ -0,0 +1,9 @@
+class Ring_buffer:
+    def __init__(self,size):
+        self.size = size
+        self.data = []
+
+    def append(self, data):
+        self.data.append(data)
+        if len(self.data) == self.size:
+            self.data.pop(0)
\ No newline at end of file