diff --git a/freedata_server/arq_session.py b/freedata_server/arq_session.py
index 99313b1c..d92f1d48 100644
--- a/freedata_server/arq_session.py
+++ b/freedata_server/arq_session.py
@@ -36,12 +36,12 @@ class ARQSession:
             'duration_per_frame': 6.5,
             'bandwidth': 2438,
         },
-        4: {
-            'mode': codec2.FREEDV_MODE.qam16c2,
-            'min_snr': 11,
-            'duration_per_frame': 2.8,
-            'bandwidth': 2438,
-        },
+        #4: {
+        #    'mode': codec2.FREEDV_MODE.qam16c2,
+        #    'min_snr': 11,
+        #    'duration_per_frame': 2.8,
+        #    'bandwidth': 2438,
+        #},
     }
 
     def __init__(self, config: dict, modem, dxcall: str, state_manager):
diff --git a/freedata_server/codec2.py b/freedata_server/codec2.py
index fe7b785e..54ec7d36 100644
--- a/freedata_server/codec2.py
+++ b/freedata_server/codec2.py
@@ -37,7 +37,7 @@ class FREEDV_MODE(Enum):
     data_ofdm_500 = 21500
     data_ofdm_2438 = 2124381
     #data_qam_2438 = 2124382
-    qam16c2 = 22
+    #qam16c2 = 22
 
 class FREEDV_MODE_USED_SLOTS(Enum):
     """
diff --git a/freedata_server/demodulator.py b/freedata_server/demodulator.py
index b72973e1..491b6e51 100644
--- a/freedata_server/demodulator.py
+++ b/freedata_server/demodulator.py
@@ -119,7 +119,7 @@ class Demodulator():
         for mode in self.MODE_DICT:
             # Start decoder threads
             self.MODE_DICT[mode]['decoding_thread'] = threading.Thread(
-                target=self.demodulate_audio,args=[mode], name=self.MODE_DICT[mode]['name'], daemon=True
+                target=self.demodulate_audio,args=[mode], name=self.MODE_DICT[mode]['name'], daemon=False
             )
             self.MODE_DICT[mode]['decoding_thread'].start()
 
diff --git a/freedata_server/modulator.py b/freedata_server/modulator.py
index 91f1085e..6dbe2147 100644
--- a/freedata_server/modulator.py
+++ b/freedata_server/modulator.py
@@ -26,7 +26,7 @@ class Modulator:
         self.freedv_datac14_tx = codec2.open_instance(codec2.FREEDV_MODE.datac14.value)
         self.data_ofdm_500_tx = codec2.open_instance(codec2.FREEDV_MODE.data_ofdm_500.value)
         self.data_ofdm_2438_tx = codec2.open_instance(codec2.FREEDV_MODE.data_ofdm_2438.value)
-        self.freedv_qam16c2_tx = codec2.open_instance(codec2.FREEDV_MODE.qam16c2.value)
+        #self.freedv_qam16c2_tx = codec2.open_instance(codec2.FREEDV_MODE.qam16c2.value)
         #self.data_qam_2438_tx = codec2.open_instance(codec2.FREEDV_MODE.data_qam_2438.value)
 
     def transmit_add_preamble(self, buffer, freedv):
diff --git a/freedata_server/schedule_manager.py b/freedata_server/schedule_manager.py
index 67f5f0dd..3bfb9196 100644
--- a/freedata_server/schedule_manager.py
+++ b/freedata_server/schedule_manager.py
@@ -50,7 +50,7 @@ class ScheduleManager:
             self.scheduler.enter(0, 1, self.schedule_event, (event_info['function'], event_info['interval']))
 
         # Run the scheduler in a separate thread
-        self.scheduler_thread = threading.Thread(target=self.scheduler.run, daemon=True)
+        self.scheduler_thread = threading.Thread(target=self.scheduler.run, daemon=False)
         self.scheduler_thread.start()
 
     def stop(self):
diff --git a/freedata_server/server.py b/freedata_server/server.py
index d9115948..78a6f53a 100644
--- a/freedata_server/server.py
+++ b/freedata_server/server.py
@@ -380,7 +380,7 @@ def main():
     if not modemport:
         modemport = 5000
 
-    app.run(modemaddress, modemport)
+    app.run(modemaddress, modemport, debug=False)
 
 if __name__ == "__main__":
     main()
diff --git a/freedata_server/service_manager.py b/freedata_server/service_manager.py
index 43b21515..54027ecd 100644
--- a/freedata_server/service_manager.py
+++ b/freedata_server/service_manager.py
@@ -22,7 +22,7 @@ class SM:
         self.socket_interface_manager = None
 
         runner_thread = threading.Thread(
-            target=self.runner, name="runner thread", daemon=True
+            target=self.runner, name="runner thread", daemon=False
         )
         runner_thread.start()
 
@@ -66,6 +66,9 @@ class SM:
             else:
                 self.log.warning("[SVC] freedata_server command processing failed", cmd=cmd, state=self.state_manager.is_modem_running)
 
+            # finally clear processing commands
+            self.modem_service.queue.clear()
+
     def start_modem(self):
 
         if self.config['STATION']['mycall'] in ['XX1XXX']:
@@ -76,10 +79,8 @@ class SM:
             self.log.warning("freedata_server already running")
             return False
 
-
         # test audio devices
         audio_test = self.test_audio()
-
         if False in audio_test or None in audio_test or self.state_manager.is_modem_running:
             self.log.warning("starting freedata_server failed", input_test=audio_test[0], output_test=audio_test[1])
             self.state_manager.set("is_modem_running", False)
@@ -104,13 +105,13 @@ class SM:
         
     def stop_modem(self):
         self.log.info("stopping freedata_server....")
-        self.modem.stop_modem()
-        del self.modem
-        self.modem = False
+        if self.modem:
+            self.modem.stop_modem()
+            del self.modem
+            self.modem = False
         self.state_manager.set("is_modem_running", False)
         self.schedule_manager.stop()
         self.event_manager.modem_stopped()
-
     def test_audio(self):
         try:
             audio_test = audio.test_audio_devices(self.config['AUDIO']['input_device'],