diff --git a/hblink.py b/hblink.py
index d9ead1b..5f433fc 100755
--- a/hblink.py
+++ b/hblink.py
@@ -468,6 +468,7 @@ class HBSYSTEM(DatagramProtocol):
                 _stream_id = _data[16:20]
                 if not bool(_stream_id):
                     logger.warning('(%s) CALL DROPPED AS STREAM ID IS NULL FROM SUBSCRIBER %s', self._system, int_id(_rf_src))
+                    return
                 #logger.debug('(%s) DMRD - Seqence: %s, RF Source: %s, Destination ID: %s', self._system, _seq, int_id(_rf_src), int_id(_dst_id))
                 # ACL Processing
                 if self._CONFIG['GLOBAL']['USE_ACL']:
@@ -696,6 +697,9 @@ class HBSYSTEM(DatagramProtocol):
                     _frame_type = (_bits & 0x30) >> 4
                     _dtype_vseq = (_bits & 0xF) # data, 1=voice header, 2=voice terminator; voice, 0=burst A ... 5=burst F
                     _stream_id = _data[16:20]
+                    if not bool(_stream_id):
+                        logger.warning('(%s) CALL DROPPED AS STREAM ID IS NULL FROM SUBSCRIBER %s', self._system, int_id(_rf_src))
+                        return
                     #logger.debug('(%s) DMRD - Sequence: %s, RF Source: %s, Destination ID: %s', self._system, int_id(_seq), int_id(_rf_src), int_id(_dst_id))
 
                     # ACL Processing