diff --git a/src/Network/fgcom.cxx b/src/Network/fgcom.cxx
index 6ee912d..e82e8fa 100644
--- a/src/Network/fgcom.cxx
+++ b/src/Network/fgcom.cxx
@@ -326,6 +326,9 @@ void FGCom::postinit()
     iaxc_input_level_set( 0.0 );
     iaxc_output_level_set(getCurrentCommVolume());
 
+    SG_LOG(SG_IO, SG_INFO, "FGCom: Mute the mic and set speaker at start " << getCurrentCommVolume());
+
+
     iaxc_millisleep(50);
 
     // Do the first call at start
@@ -343,8 +346,8 @@ double FGCom::getCurrentCommVolume() const {
         rv = rv * _commVolumeNode->getFloatValue();
 
 //zhongjin
-//    return rv;
-    return 1.0;
+    rv = 0.9;
+    return rv;
 }
 double FGCom::getCurrentFrequencyKhz() const {
     return 10 * static_cast<int>(_currentCommFrequency * 100 + 0.25); 
@@ -402,6 +405,9 @@ void FGCom::setupCommFrequency(int channel) {
 }
 
 void FGCom::connectToCommFrequency() {
+
+    SG_LOG(SG_IO, SG_INFO, "FGCom: connectToCommFrequency" );
+
     // ensure that the current comm is still in range
     if ((_currentCallFrequency > 0.0) && !isInRange(_currentCallFrequency)) {
         SG_LOG(SG_IO, SG_WARN, "FGCom: call out of range of: " << _currentCallFrequency);
@@ -484,13 +490,15 @@ void FGCom::shutdown()
   _initialized = false;
   _enabled = false;
 
+  SG_LOG(SG_IO, SG_INFO, "FGCom: shutdown" );
+
   iaxc_set_event_callback(NULL);
   iaxc_unregister(_regId);
   iaxc_stop_processing_thread();
   iaxc_shutdown();
 
-    // added to help debugging lingering IAX thread after fgOSCloseWindow
-    flightgear::addSentryBreadcrumb("Did shutdown FGCom", "info");
+  // added to help debugging lingering IAX thread after fgOSCloseWindow
+  flightgear::addSentryBreadcrumb("Did shutdown FGCom", "info");
     
   assert( static_instance == this );
   static_instance = NULL;
@@ -520,6 +528,9 @@ void FGCom::valueChanged(SGPropertyNode *prop)
   }
 
   if (prop == _commVolumeNode && _enabled) {
+
+      SG_LOG(SG_IO, SG_INFO, "FGCom: prop = _commVolumeNode" );
+
       if (_ptt_node->getIntValue()) {
           SG_LOG(SG_IO, SG_INFO, "FGCom: ignoring change comm volume as PTT pressed");
       }
@@ -542,6 +553,9 @@ void FGCom::valueChanged(SGPropertyNode *prop)
   }
 
   if (prop == _ptt_node && _enabled) {
+
+      SG_LOG(SG_IO, SG_INFO, "FGCom: prop = _ptt_node" );
+
       if (_ptt_node->getIntValue()) {
           // ensure that we are on the right channel by calling setupCommFrequency  
           setupCommFrequency();
@@ -552,7 +566,8 @@ void FGCom::valueChanged(SGPropertyNode *prop)
           SG_LOG(SG_IO, SG_INFO, "FGCom: PTT active: " << _currentCallFrequency);
       }
       else {
-          iaxc_output_level_set(getCurrentCommVolume());
+          //iaxc_output_level_set(getCurrentCommVolume());
+          iaxc_output_level_set(0.9);
           iaxc_input_level_set(0.0);
           SG_LOG(SG_IO, SG_INFO, "FGCom: PTT release: " << _currentCallFrequency << " vol=" << getCurrentCommVolume());
           _mpTransmitFrequencyNode->setValue(0);