diff --git a/code/location.py b/code/location.py
index 679d0f7..cccd69c 100644
--- a/code/location.py
+++ b/code/location.py
@@ -92,6 +92,7 @@ class GPS(Singleton):
             break
 
         self.break_flag = 0
+        log.debug('utc_time: %s' % self.read_location_utc(data))
         return data
 
     def quecgnss_read(self):
@@ -145,6 +146,14 @@ class GPS(Singleton):
                 return speed_re.group(0)[3:-3]
         return ""
 
+    def read_location_utc(self, gps_data):
+        gga_data = self.read_location_GxGGA(gps_data)
+        if gga_data:
+            utc_re = ure.search(r"GGA,[0-9]+\.[0-9]+,", gga_data)
+            if utc_re:
+                return utc_re.group(0)[4:-1]
+        return ""
+
     def read_quecIot(self):
         data = []
         gps_data = self.read()
diff --git a/code/remote.py b/code/remote.py
index 50466c3..0aa93ff 100644
--- a/code/remote.py
+++ b/code/remote.py
@@ -161,6 +161,8 @@ def uplink_process(argv):
         # Read history data that didn't send to server intime to hist-dictionary.
         hist = self.read_history()
         try:
+            if self.tracker.net_enable is False:
+                raise RemoteError('Net Is Disconnected.')
             for key, value in hist.items():
                 # Check if non_loca data (sensor or device info data) or location gps data or location non-gps data (cell/wifi-locator data)
                 if key == 'hist_data':
@@ -193,27 +195,16 @@ def uplink_process(argv):
                 # Flush data in hist-dictionary to tracker_data.hist file.
                 self.refresh_history(hist)
 
-            '''
-            If history data exists, put a empty msg to uplink_queue to trriger the return of self.uplink_queue.get() API below.
-            So that history data could be processed again immediately.
-            Without this, history data could only be processed after new data being put into uplink_queue.
-            But is this necessary ???
-            '''
-            # TODO: dataCall nw_callback to put
-            if len(hist.get('hist_data', [])):
-                self.uplink_queue.put(())
-
         # When comes to this, wait for new data coming into uplink_queue.
         data = self.uplink_queue.get()
         if data:
             if data[1]:
-                if not self.cloud.post_data(data[1]):
-                    self.add_history(data[1])
-                    sys_bus.publish(data[0], 'false')
-                else:
-                    sys_bus.publish(data[0], 'true')
-            else:
-                sys_bus.publish(data[0], 'true')
+                if self.tracker.net_enable is True:
+                    if self.cloud.post_data(data[1]):
+                        sys_bus.publish(data[0], 'true')
+                        continue
+                self.add_history(data[1])
+            sys_bus.publish(data[0], 'false')
 
 
 class Remote(Singleton):
diff --git a/code/settings.py b/code/settings.py
index cc893ed..95796d2 100644
--- a/code/settings.py
+++ b/code/settings.py
@@ -122,7 +122,7 @@ class default_values_app(object):
 
     work_mode = _work_mode.cycle
 
-    work_cycle_period = 60
+    work_cycle_period = 30
 
     low_power_alert_threshold = 20
 
@@ -192,7 +192,7 @@ class default_values_sys(object):
 
     ota_status = _ota_status.none
 
-    cloud = _cloud.quecIot
+    cloud = _cloud.AliYun
 
     cloud_init_params = {}
 
diff --git a/code/tracker.py b/code/tracker.py
index 3f85cad..62f06fd 100644
--- a/code/tracker.py
+++ b/code/tracker.py
@@ -50,6 +50,8 @@ class Tracker(Singleton):
         self.num_iter = numiter()
         self.num_lock = _thread.allocate_lock()
 
+        self.net_enable = True
+
         if PowerKey is not None:
             self.power_key = PowerKey()
             self.power_key.powerKeyEventRegister(self.pwk_callback)
@@ -105,10 +107,12 @@ class Tracker(Singleton):
         sensor_check_res = self.check.sensor_check()
 
         if net_check_res == (3, 1) and gps_check_res and sensor_check_res:
+            self.net_enable = True
             self.running_led.period = 2
         else:
             self.running_led.period = 0.5
             if net_check_res != (3, 1):
+                self.net_enable = False
                 fault_code = 20001
                 alert_info = {'fault_code': fault_code, 'local_time': utime.mktime(utime.localtime())}
                 alert_data_res = self.get_alert_data(alert_code, alert_info)
@@ -215,15 +219,15 @@ class Tracker(Singleton):
     def nw_callback(self, args):
         net_check_res = self.check.net_check()
         if args[1] != 1:
-            # TODO: Check Internet disconected then do something
-            if net_check_res[0] == 0 or (net_check_res[0] == 1 and net_check_res[1] == 0):
+            self.net_enable = False
+            if net_check_res == (1, 0):
                 alert_code = 30004
                 alert_info = {'local_time': utime.mktime(utime.localtime())}
                 alert_data = self.get_alert_data(alert_code, alert_info)
                 self.device_data_report(event_data=alert_data)
         else:
-            # TODO: Check Internet conected then do something
-            pass
+            if net_check_res == (3, 1):
+                self.net_enable = True
 
 
 class SelfCheck(object):