diff --git a/src/Network/fgcom.cxx b/src/Network/fgcom.cxx
index 5cd4904..b7380db 100644
--- a/src/Network/fgcom.cxx
+++ b/src/Network/fgcom.cxx
@@ -621,7 +621,7 @@ void FGCom::valueChanged(SGPropertyNode *prop)
       {
           iaxc_input_level_set(0.0);
 //          iaxc_output_level_set(getCurrentCommVolume());
-          iaxc_output_level_set(1.0);
+          iaxc_output_level_set(0.8);
 //          SG_LOG(SG_SOUND, SG_ALERT, "FGCom: change comm volume=" << _commVolumeNode->getFloatValue());
       }
   }
@@ -677,14 +677,15 @@ void FGCom::valueChanged(SGPropertyNode *prop)
           SG_LOG(SG_SOUND, SG_INFO, "CMD :" << urlcmd );
           popen(urlcmd.c_str(),"r");
 
-          iaxc_output_level_set(1.0);
+          mesPopup("PTT释放",3);
+          iaxc_millisleep(1000);
+
+          iaxc_output_level_set(0.8);
           iaxc_input_level_set(0.0);
 //          SG_LOG(SG_SOUND, SG_ALERT, "FGCom: PTT release: " << _currentCallFrequency << " vol=" << getCurrentCommVolume());
           _mpTransmitFrequencyNode->setValue(0);
           _mpTransmitPowerNode->setValue(0);
 
-//          fgSetString("/sim/screen/white","PTT释放");
-          mesPopup("PTT释放",3);
 
       }
   }
@@ -724,9 +725,9 @@ void FGCom::valueChanged(SGPropertyNode *prop)
 
   if (prop == _speakerLevel_node && _enabled) {
     float speakerLevel = prop->getFloatValue();
-    SG_CLAMP_RANGE<float>( speakerLevel, 0.0, 1.0 );
+    SG_CLAMP_RANGE<float>( speakerLevel, 0.0, 0.8 );
 
-    speakerLevel=1.0;
+    speakerLevel=0.8;
 
     _speakerLevel_node->setFloatValue(speakerLevel);
     iaxc_output_level_set(speakerLevel);
@@ -765,7 +766,7 @@ void FGCom::testMode(bool testMode)
       iaxc_input_level_set( 0.0 );
       //iaxc_output_level_set(getCurrentCommVolume());
 
-      iaxc_output_level_set(1.0);
+      iaxc_output_level_set(0.8);
 
       
       _currentCallIdent = -1;