diff --git a/hblink.py b/hblink.py
index 0a6c44f..b978302 100755
--- a/hblink.py
+++ b/hblink.py
@@ -439,7 +439,7 @@ class OPENBRIDGE(DatagramProtocol):
                         return
                     
                     #Discard bad source server 
-                    if (len(str(int.from_bytes(_source_server,'big'))) < 4) or (len(str(int.from_bytes(_source_server,'big'))) > 7)  and int.from_bytes(_source_server,'big') > 0:
+                    if ((len(str(int.from_bytes(_source_server,'big'))) < 4) or (len(str(int.from_bytes(_source_server,'big'))) > 7)) and int.from_bytes(_source_server,'big') > 0:
                         if _stream_id not in self._laststrid:
                             logger.warning('(%s) Source Server should be  between 4 and 7 digits, discarding Src: %s', self._system, int.from_bytes(_source_server,'big'))
                             self.send_bcsq(_dst_id,_stream_id)