diff --git a/src/com.cpp b/src/com.cpp
index b9151fd..01f9292 100644
--- a/src/com.cpp
+++ b/src/com.cpp
@@ -93,29 +93,34 @@ T_com::~T_com()
 
 void T_com::ser_ISR100ms()
 {
+    //qDebug() << "~~>LIB" << "ENTER...";
     // call every 100ms to check if user(HMI) wants to connect or disconnect
-
-    //qDebug() << "~~>LIB" << "checking connect button... " ;
-
     uint8_t chkConn = gpi_getSerialConn();    // from global GUI buffer (Sdata)
+
+    //qDebug() << "~~>LIB" << "checking connect button... " << chkConn;
+
     switch (chkConn)
     {
         case 0: // 0 button "connect" was just released
+                //qDebug() << "close serial port" << chkConn;
                 closeSerialPort();
                 gpi_serialChanged();    // set chkConn to 2, thus getting edge
                 break;
         case 1: // 1 button "connect" was just pressed
+                //qDebug() << "open serial port" << chkConn;
                 open_Serial_Port();
                 gpi_serialChanged();    // set chkConn to 2, thus getting edge
                 break;
     }
 
 
-    if (CatSerial->isOpen())
+    if (CatSerial->isOpen()) {
         gpi_serialIsOpen(true);
-    else
+    } else {
         gpi_serialIsOpen(false);
+    }
 
+    //qDebug() << "LEAVE " << chkConn;
 }
 
 // -------------------------------------------------------------------------------------------------------------
@@ -124,17 +129,24 @@ void T_com::ser_ISR100ms()
 
 char T_com::open_Serial_Port()
 {
+    //qDebug() << "ENTER";
+
     bool ret;
     QString myString=nullptr, myPortName=nullptr, myBaudStr=nullptr;
     int myBaudNr;
 
-    if (CatSerial->isOpen())
+    if (CatSerial->isOpen()) {
+        qDebug() << "!!!IS OPEN!!!";
         return 0;                   // opening twice is not allowed
+    }
 
     //qDebug() << "connecting..." << myPortName;
     myPortName=gpi_getComPortName();                // was selected and stored from GUI
     CatSerial->setPortName(myPortName);
     myBaudNr=gpi_getBaudNr();                       // was selected and stored from GUI
+
+    //qDebug() << "myPortName" << myPortName << ", myBaudNr" << myBaudNr;
+
     switch (myBaudNr)
     {
         // 0:1200   1:9600   2:19200   3:38400   4:57600   5:115200
@@ -167,6 +179,9 @@ char T_com::open_Serial_Port()
         myString.append(CatSerial->errorString());
         qDebug() << myString;
         gpi_setTxt4comStateLine(myString);
+
+        //qDebug() << "LEAVE";
+
         return 0;
     } else
     {
@@ -182,11 +197,14 @@ char T_com::open_Serial_Port()
 
     }
 
-     return 0;
+    //qDebug() << "LEAVE";
+    return 0;
 }
 
 void T_com::closeSerialPort()
 {
+    //qDebug() << "ENTER";
+
     if (CatSerial->isOpen())
     {
         qDebug() << "closing connection";
@@ -195,6 +213,8 @@ void T_com::closeSerialPort()
         gpi_setTxt4RsDiagWin("closed");
 
     }
+
+    //qDebug() << "LEAVE";
 }