Index: sources/canbus/messagehandler.h
===================================================================
diff -u -rf36dd9c29f633b54bf7f0232093ecaefa5452ca8 -r4c53c7c62df7562a6c0915f0c5af7ea0ed884ca3
--- sources/canbus/messagehandler.h	(.../messagehandler.h)	(revision f36dd9c29f633b54bf7f0232093ecaefa5452ca8)
+++ sources/canbus/messagehandler.h	(.../messagehandler.h)	(revision 4c53c7c62df7562a6c0915f0c5af7ea0ed884ca3)
@@ -68,9 +68,9 @@
     // friends
     friend class ::unittests;
 
-    const QHash<GuiActionType ,char> payloadLen {
-        {GuiActionType::PowerOff, 0x01},
-        {GuiActionType::Check_In, 0x00}
+    const QHash<GuiActionType ,quint8> payloadLen {
+        {GuiActionType::PowerOff,   1},
+        {GuiActionType::Check_In,   0}
     };
 
     // constants
@@ -82,6 +82,7 @@
     enum Frame_Data : quint8 {
         eLenCanFrame        =   8,
         eLenMaxHeaderData   =   3,
+        eLenMaxData         = 255,
 
         eLenSyncByte        =   1,
         eLenActionId        =   2,
@@ -134,16 +135,15 @@
     void initConnections();
     void checked_in();
 
-    void transmitFrame(MessageHandler::Can_Id vCan_Id, GuiActionType vAction, GuiActionData vData = GuiActionData::NoData);
+    void transmitFrame(MessageHandler::Can_Id vCan_Id, GuiActionType vAction, const QByteArray &vData = 0);
 
     bool ignoreChannel(const QCanBusFrame &vFrame);
 
     // build message to be sent
-    QByteArray    buildMessage (GuiActionType vAction , GuiActionData vData);
+    QList<QByteArray> buildMessage(GuiActionType vAction , const QByteArray &vData);
     void          addSyncByte  (QByteArray   &vPayload);
     void          addActionId  (QByteArray   &vPayload, GuiActionType vAction);
-    void          addLegth     (QByteArray   &vPayload, GuiActionType vAction);
-    void          addData      (QByteArray   &vPayload, GuiActionData vData);
+    void          addData      (QByteArray   &vPayload, GuiActionType vAction, const QByteArray &vData);
     void          addCRC       (QByteArray   &vPayload);
     void          addPadding   (QByteArray   &vPayload);
 
@@ -152,7 +152,7 @@
     bool          checkCRC     (const QByteArray &vData, quint8 vCRC);
 
     // strip message to its parts
-    bool          stripMessage(const QCanBusFrame &vFrame, Message &vMessage);
+    bool          stripMessage (const QCanBusFrame &vFrame, Message &vMessage);
     bool          hasSyncByte  (QByteArray   &vPayload);
     GuiActionType getActionId  (QByteArray   &vPayload);
     quint8        getLength    (QByteArray   &vPayload);
@@ -162,8 +162,8 @@
     bool          interpretData(const Message &vMessage, GuiActionType &vActionId, GuiActionData &vData);
 
 private slots: // Should be private for thread safety and is connected internally.
-    void  onActionTransmit(GuiActionType vAction, GuiActionData vData); // UI => HD/DG
-    void  onFrameReceive  (const QCanBusFrame &vFrame                ); // UI <= HD/DG
+    void  onActionTransmit(GuiActionType vAction, const QByteArray &vData); // UI => HD/DG
+    void  onFrameReceive  (const QCanBusFrame &vFrame                    ); // UI <= HD/DG
 
     void onMainTimerTimeout();