diff --git a/include/interfaces.h b/include/interfaces.h
index 4ae5d46..50e1ef0 100644
--- a/include/interfaces.h
+++ b/include/interfaces.h
@@ -98,9 +98,9 @@ class hwinf
 {
 
 public:
+    enum class DownloadResult {OK, ERROR, TIMEOUT, NOP};
+
     virtual ~hwinf() {}
-               
-    
                                            
     // $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$    
     //       Use serial interface and protocol stack in Cashagent-Library
@@ -110,21 +110,19 @@ public:
     //      Furthermore the Cashagent-Library answers with status strings about sending and reading result
     // $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$    
 
-    virtual void dc_openSerial(int BaudNr, QString BaudStr, QString ComName, uint8_t connect)  const =0;
+    virtual bool dc_openSerial(int BaudNr, QString BaudStr, QString ComName, uint8_t connect) const = 0;
         // Command: open serial interface
         // BaudNr:  0:1200   1:9600   2:19200   3:38400   4:57600   5:115200
         // BaudStr: for exapmle "19200"
         // ComName: for example "COM48"
         // connect: 0, 1
 
-    virtual void dc_closeSerial(void)  const =0;
+    virtual bool dc_closeSerial(void) const = 0;
         // Command: close serial interface in order to save power while power down
         // or if another port must be used
         
-    virtual bool dc_isPortOpen(void)  const =0;
+    virtual bool dc_isPortOpen(void) const =0;
         // returns true if port open (don't send unless open. Sending to closed port will crash program)
-                   
-        
         
     virtual uint8_t test_serialState(void) const =0;
         // test on-board signals for the serials
@@ -132,7 +130,10 @@ public:
     
     virtual bool test_serialIsOn(void) const =0;      
         
-        
+    virtual bool dc_updateDC(QString binFileName,
+                             QString baudrate,
+                             QString comPort) const = 0;
+        // download binary file down into device controller
                        
     virtual void dc_autoRequest(bool on)  const =0;
         // on = true:  select that all READ-Requests are sent automatically 
@@ -1042,10 +1043,10 @@ public:
 
     virtual void bl_rebootDC(void) const =0;
 
-    virtual void bl_startBL(void) const =0;
+    virtual void bl_startBL(void) const = 0;
         // send command within 4s after DC power-on, otherwise bl is left
 
-    virtual void bl_checkBL(void) const =0;
+    virtual bool bl_checkBL(void) const = 0;
         // send command to verify if bl is up
 
     virtual bool bl_isUp(void) const =0;