diff --git a/src/Network/fgcom.cxx b/src/Network/fgcom.cxx
index f216ced..a8ceb05 100644
--- a/src/Network/fgcom.cxx
+++ b/src/Network/fgcom.cxx
@@ -244,7 +244,7 @@ void FGCom::postinit()
     }
     
     //WARNING: this _must_ be executed after sound system is totally initialized !
-    if( iaxc_initialize(NUM_CALLS) ) {
+    if( iaxc_initialize(4) ) {
         SG_LOG(SG_IO, SG_ALERT, "FGCom: cannot initialize iaxclient");
         _enabled = false;
         return;
@@ -262,14 +262,14 @@ void FGCom::postinit()
 
     iaxc_set_callerid( _callsign_node->getStringValue().c_str(), app.c_str() );
 
-    iaxc_set_formats (IAXC_FORMAT_SPEEX, IAXC_FORMAT_ULAW|IAXC_FORMAT_SPEEX);
+    //iaxc_set_formats (IAXC_FORMAT_SPEEX, IAXC_FORMAT_ULAW|IAXC_FORMAT_SPEEX);
 
-    //iaxc_set_formats (IAXC_FORMAT_GSM, IAXC_FORMAT_ULAW|IAXC_FORMAT_GSM);
+    iaxc_set_formats (IAXC_FORMAT_GSM, IAXC_FORMAT_ULAW|IAXC_FORMAT_GSM);
 
 
 
 
-    iaxc_set_speex_settings(1, 5, 0, 1, 0, 3);
+    //iaxc_set_speex_settings(1, 5, 0, 1, 0, 3);
 
     /*
      void iaxc_set_speex_settings(int decode_enhance, float quality,
@@ -277,8 +277,8 @@ void FGCom::postinit()
 
     */
 
-    iaxc_set_filters(IAXC_FILTER_AGC | IAXC_FILTER_DENOISE);
-    iaxc_set_silence_threshold(_silenceThd_node->getFloatValue());
+    //iaxc_set_filters(IAXC_FILTER_AGC | IAXC_FILTER_DENOISE);
+    //iaxc_set_silence_threshold(_silenceThd_node->getFloatValue());
     
     iaxc_start_processing_thread ();
 
@@ -315,6 +315,7 @@ void FGCom::postinit()
     //       so all following is unused finally until someone
     //       implement "multi-device" support in IAX audio driver
 
+/*
     SGPropertyNode *node     = fgGetNode("/sim/fgcom", 0, true);
 
     struct iaxc_audio_device *devs;
@@ -360,28 +361,21 @@ void FGCom::postinit()
       if( devs[i].capabilities & IAXC_AD_OUTPUT_DEFAULT )
         _selectedOutput_node->setIntValue(devs[i].devID);
     }
+*/
 
-    // Mute the mic and set speaker at start
-    iaxc_input_level_set( 0.0 );
-    //iaxc_output_level_set(getCurrentCommVolume());
+    iaxc_input_level_set(0.0);
     iaxc_output_level_set(1.0);
 
-
-    iaxc_millisleep(50);
+    iaxc_millisleep(300);
 
 
     // Do the first call at start
     setupCommFrequency();
 
-    iaxc_millisleep(500);
-
     connectToCommFrequency();
 
     SG_LOG(SG_SOUND, SG_INFO, "FGCom: postinit 初始化完成");
 
-    iaxc_millisleep(500);
-
-    iaxc_output_level_set(1.0);
 
 
 }