diff --git a/config_SAMPLE.py b/config_SAMPLE.py
index 6930087..e4efcda 100644
--- a/config_SAMPLE.py
+++ b/config_SAMPLE.py
@@ -9,6 +9,7 @@ HBLINK_PORT     = 4321                           # HBlink's TCP reporting socket
 FREQUENCY       = 10                             # Frequency to push updates to web clients
 CLIENT_TIMEOUT  = 0                              # Clients are timed out after this many seconds, 0 to disable
 
+# If you are using FreeDMR you should not use it OPB_FILTER. It only for HBLink
 # To prevent show local traffic on the which is shown as an "echo" from all OBPs, 
 # we need to add in OPB_FILTER NETWORK ID for all defined OPB links on our own server. 
 # It is for show the real system from which traffic originates from.