diff --git a/dsmr_parser/clients/serial_.py b/dsmr_parser/clients/serial_.py
index 7adbc46..d8bc529 100644
--- a/dsmr_parser/clients/serial_.py
+++ b/dsmr_parser/clients/serial_.py
@@ -100,7 +100,7 @@ class AsyncSerialReader(SerialReader):
         """
         Read complete DSMR telegram's from the serial interface and return a Telegram object.
         
-        :rtype: generator
+        :rtype: None
         """
 
         # create Serial StreamReader