diff --git a/include/interfaces.h b/include/interfaces.h
index 51ec7e1..0aa4a1e 100755
--- a/include/interfaces.h
+++ b/include/interfaces.h
@@ -414,6 +414,7 @@ struct T_bna
 
 };
 
+class DownloadThread;
 class hwinf
 {
 
@@ -2299,9 +2300,73 @@ public:
     //                                          countOfBills[1] for 10€   and so on
 
 
+    // download device controller
+    virtual bool dcDownloadRequest(QString const &fileToDownload) const {
+        Q_UNUSED(fileToDownload);
+        return false;
+    }
+    virtual bool dcDownloadRequested() const { return false; }
+    virtual bool dcDownloadResetRequest() const { return false; }
+    virtual bool dcDownloadRequestAck() const { return false; }
+    virtual bool dcDownloadRunning() const { return false; }
+    virtual bool dcDownloadFinished() { return false; }
+
+    virtual bool dcDownloadReportStart() const { return false; }
+    virtual bool dcDownloadReportRunning() const { return true; }
+    virtual bool dcDownloadReportFinished() { return true; }
+
+    virtual bool dcDownloadThreadStart() { return false; }
+    virtual bool dcDownloadThreadRunning() const { return true; }
+    virtual void dcDownloadThreadFinalize(DownloadThread *) {}
+    virtual bool dcDownloadThreadFinished() const { return true; }
+    virtual bool dcDownloadReportThreadStart() { return false; }
+    virtual bool dcDownloadReportThreadRunning() const { return true; }
+    virtual void dcDownloadReportThreadFinalize() {}
+    virtual void dcDownloadReportThreadQuit() {}
+    virtual bool dcDownloadReportThreadFinished() const { return true; }
+
+
+    virtual QString dcDownloadFileName() const { return ""; }
+    virtual bool dcDownloadSetRequested(bool requested) {
+       Q_UNUSED(requested); return false;
+    }
+    virtual bool dcDownloadSetRunning(bool running) {
+       Q_UNUSED(running); return false;
+    }
+    virtual bool dcDownloadSetFinished(bool finished) {
+       Q_UNUSED(finished); return false;
+    }
+    virtual void dcDownloadSetTotalBlockNumber(uint16_t totalBlockNumber) {
+       Q_UNUSED(totalBlockNumber);
+    }
+    virtual void dcDownloadSetCurrentBlockNumber(uint16_t currentBlockNumber) {
+       Q_UNUSED(currentBlockNumber);
+    }
+    virtual bool dcDownloadGetRequested() const { return false; }
+    virtual bool dcDownloadGetRunning() const { return false; }
+    virtual bool dcDownloadGetFinished() const { return false; }
+    virtual uint16_t dcDownloadGetTotalBlockNumber() const { return 0; }
+    virtual uint16_t dcDownloadGetCurrentBlockNumber() const { return 0; }
+
+    virtual QObject const *getAPI() { return nullptr; }
 
 
 signals:
+    /*
+        NOTE: the difference between a virtual Qt signal and a normal Qt signal:
+        A Qt virtual signal is a connection that is established using a pointer
+        or reference and is not connected to an object or data. It is therefore
+        not bound to a particular object, but to a specific class (object type).
+        Qt virtual signals are useful because they allow you to create
+        connections without worrying about whether an object or a specific data
+        element has been destroyed.
+        https://www.youtube.com/watch?v=HTH3VFfqsXw
+
+     */
+    virtual void hwapi_reportDCDownloadStatus(QString const&) const {}
+    virtual void hwapi_reportDCDownloadSuccess(QString const&) const {}
+    virtual void hwapi_reportDCDownloadFailure(QString const&) const {}
+
     virtual void hwapi_templatePrintFinished_OK(void) const=0;
     virtual void hwapi_templatePrintFinished_Err(void) const=0;