diff --git a/src/ebusd/bushandler.cpp b/src/ebusd/bushandler.cpp
index 277bc9f9..ccd1d0fa 100644
--- a/src/ebusd/bushandler.cpp
+++ b/src/ebusd/bushandler.cpp
@@ -350,7 +350,7 @@ result_t BusHandler::readFromBus(Message* message, const string& inputStr, symbo
   return ret;
 }
 
-void BusHandler::notifyProtocolStatus(ProtocolState state) {
+void BusHandler::notifyProtocolStatus(ProtocolState state, result_t result) {
   if (state == ps_empty && m_pollInterval > 0) {  // check for poll/scan
     time_t now;
     time(&now);
diff --git a/src/ebusd/bushandler.h b/src/ebusd/bushandler.h
index fe6527b7..7bc185db 100755
--- a/src/ebusd/bushandler.h
+++ b/src/ebusd/bushandler.h
@@ -396,7 +396,7 @@ class BusHandler : public ProtocolListener {
   void setScanConfigLoaded(symbol_t address, const string& file);
 
   // @copydoc
-  void notifyProtocolStatus(ProtocolState state) override;
+  void notifyProtocolStatus(ProtocolState state, result_t result) override;
 
   // @copydoc
   result_t notifyProtocolAnswer(const MasterSymbolString& master, SlaveSymbolString* slave) override;
diff --git a/src/lib/ebus/protocol.cpp b/src/lib/ebus/protocol.cpp
index fa31bd4c..95157c92 100644
--- a/src/lib/ebus/protocol.cpp
+++ b/src/lib/ebus/protocol.cpp
@@ -32,6 +32,18 @@ using std::hex;
 using std::setfill;
 using std::setw;
 
+const char* getProtocolStateCode(ProtocolState state) {
+  switch (state) {
+    case ps_noSignal: return "no signal";
+    case ps_idle:     return "idle";
+    case ps_idleSYN:  return "idle, SYN generator";
+    case ps_recv:     return "receive";
+    case ps_send:     return "send";
+    case ps_empty:    return "idle, empty";
+    default:          return "unknown";
+  }
+}
+
 bool ActiveBusRequest::notify(result_t result, const SlaveSymbolString& slave) {
   if (result == RESULT_OK) {
     string str = slave.getStr();
diff --git a/src/lib/ebus/protocol.h b/src/lib/ebus/protocol.h
index 1936d3ec..183826e1 100755
--- a/src/lib/ebus/protocol.h
+++ b/src/lib/ebus/protocol.h
@@ -89,9 +89,18 @@ typedef struct ebus_protocol_config {
 enum ProtocolState {
   ps_noSignal,   //!< no signal on the bus
   ps_idle,       //!< idle (after @a SYN symbol)
+  ps_idleSYN,    //!< idle (after sent SYN symbol in acting as SYN generator)
+  ps_recv,       //!< receiving
+  ps_send,       //!< sending
   ps_empty,      //!< idle, no more lock remaining, and no other request queued
 };
 
+/**
+ * Return the string corresponding to the @a ProtocolState.
+ * @param state the @a ProtocolState.
+ * @return the string corresponding to the @a ProtocolState.
+ */
+const char* getProtocolStateCode(ProtocolState state);
 
 class ProtocolHandler;
 
@@ -208,8 +217,9 @@ class ProtocolListener {
   /**
    * Called to notify a status update from the protocol.
    * @param state the current protocol state.
+   * @param result the error code reason for the state change, or @a RESULT_OK.
    */
-  virtual void notifyProtocolStatus(ProtocolState state) = 0;  // abstract
+  virtual void notifyProtocolStatus(ProtocolState state, result_t result) = 0;  // abstract
 
   /**
    * Called to notify a new valid seen address on the bus.
@@ -253,7 +263,7 @@ class ProtocolHandler : public WaitThread, DeviceListener {
   ProtocolHandler(const ebus_protocol_config_t config,
       Device* device, ProtocolListener* listener)
     : WaitThread(), m_config(config), m_device(device), m_listener(listener),
-      m_reconnect(false),
+      m_listenerState(ps_noSignal), m_reconnect(false),
       m_ownMasterAddress(config.ownAddress), m_ownSlaveAddress(getSlaveAddress(config.ownAddress)),
       m_addressConflict(false),
       m_masterCount(config.readOnly ? 0 : 1),
@@ -519,6 +529,9 @@ class ProtocolHandler : public WaitThread, DeviceListener {
   /** the @a ProtocolListener. */
   ProtocolListener *m_listener;
 
+  /** the last state the listener was informed with. */
+  ProtocolState m_listenerState;
+
   /** set to @p true when the device shall be reconnected. */
   bool m_reconnect;
 
diff --git a/src/lib/ebus/protocol_direct.cpp b/src/lib/ebus/protocol_direct.cpp
index 28fe84ab..6b789e23 100644
--- a/src/lib/ebus/protocol_direct.cpp
+++ b/src/lib/ebus/protocol_direct.cpp
@@ -135,7 +135,7 @@ result_t DirectProtocolHandler::handleSymbol() {
     if (!m_device->isArbitrating() && m_currentRequest == nullptr && m_remainLockCount == 0) {
       BusRequest* startRequest = m_nextRequests.peek();
       if (startRequest == nullptr) {
-        m_listener->notifyProtocolStatus(ps_empty);
+        m_listener->notifyProtocolStatus(ps_empty, RESULT_OK);
         startRequest = m_nextRequests.peek();
       }
       if (startRequest != nullptr) {  // initiate arbitration
@@ -677,9 +677,6 @@ result_t DirectProtocolHandler::setState(BusState state, result_t result, bool f
   }
 
   if (state == bs_noSignal) {  // notify all requests
-    if (m_state != bs_noSignal) {
-      m_listener->notifyProtocolStatus(ps_idle);
-    }
     m_response.clear();  // notify with empty response
     while ((m_currentRequest = m_nextRequests.pop()) != nullptr) {
       bool restart = m_currentRequest->notify(RESULT_ERR_NO_SIGNAL, m_response);
@@ -692,12 +689,13 @@ result_t DirectProtocolHandler::setState(BusState state, result_t result, bool f
         m_finishedRequests.push(m_currentRequest);
       }
     }
-  } else if (m_state == bs_noSignal) {
-    m_listener->notifyProtocolStatus(ps_noSignal);
   }
 
   m_escape = 0;
   if (state == m_state) {
+    if (m_listener && result != RESULT_OK) {
+      m_listener->notifyProtocolStatus(m_listenerState, result);
+    }
     return result;
   }
   if ((result < RESULT_OK && !(result == RESULT_ERR_TIMEOUT && state == bs_skip && m_state == bs_ready))
@@ -718,6 +716,16 @@ result_t DirectProtocolHandler::setState(BusState state, result_t result, bool f
       logNotice(lf_bus, "signal acquired");
     }
   }
+  if (m_listener) {
+    ProtocolState pstate = protocolStateByBusState[state];
+    if (pstate == ps_idle && m_generateSynInterval == SYN_INTERVAL) {
+      pstate = ps_idleSYN;
+    }
+    if (result != RESULT_OK || pstate != m_listenerState) {
+      m_listener->notifyProtocolStatus(pstate, result);
+      m_listenerState = pstate;
+    }
+  }
   m_state = state;
 
   if (state == bs_ready || state == bs_skip) {