diff --git a/notificationservice-base/docker/ptptrackingfunction/trackingfunctionsdk/common/helpers/constants.py b/notificationservice-base/docker/ptptrackingfunction/trackingfunctionsdk/common/helpers/constants.py
index 6c0c1ef..8e9e2a2 100644
--- a/notificationservice-base/docker/ptptrackingfunction/trackingfunctionsdk/common/helpers/constants.py
+++ b/notificationservice-base/docker/ptptrackingfunction/trackingfunctionsdk/common/helpers/constants.py
@@ -27,9 +27,7 @@ MASTER_MODE = "master"
 TIME_IS_TRACEABLE1 = "1"
 TIME_IS_TRACEABLE2 = "true"
 GM_IS_PRESENT = "true"
-CLOCK_CLASS_VALUE1 = "6"
-CLOCK_CLASS_VALUE2 = "7"
-CLOCK_CLASS_VALUE3 = "135"
+CLOCK_CLASS_VALUE6 = "6"
 # ts2phc constants
 NMEA_SERIALPORT = "ts2phc.nmea_serialport"
 GNSS_PIN = "GNSS-1PPS"
diff --git a/notificationservice-base/docker/ptptrackingfunction/trackingfunctionsdk/common/helpers/ptpsync.py b/notificationservice-base/docker/ptptrackingfunction/trackingfunctionsdk/common/helpers/ptpsync.py
index fc3bc1a..0e88e0e 100644
--- a/notificationservice-base/docker/ptptrackingfunction/trackingfunctionsdk/common/helpers/ptpsync.py
+++ b/notificationservice-base/docker/ptptrackingfunction/trackingfunctionsdk/common/helpers/ptpsync.py
@@ -86,9 +86,7 @@ def check_results(result, total_ptp_keywords, port_count):
             and result[constants.TIME_TRACEABLE].lower != constants.TIME_IS_TRACEABLE2):
         sync_state = constants.FREERUN_PHC_STATE
     if (result[constants.GM_CLOCK_CLASS] not in
-            [constants.CLOCK_CLASS_VALUE1,
-             constants.CLOCK_CLASS_VALUE2,
-             constants.CLOCK_CLASS_VALUE3]):
+            [constants.CLOCK_CLASS_VALUE6]):
         sync_state = constants.FREERUN_PHC_STATE
     return sync_state