diff --git a/ZactuatorONOFF.ino b/ZactuatorONOFF.ino
index bedbf05..b4324c5 100644
--- a/ZactuatorONOFF.ino
+++ b/ZactuatorONOFF.ino
@@ -48,6 +48,11 @@ void MQTTtoONOFF(char * topicOri, char * datacallback){
     trc(F("MQTTtoONOFF"));
     trc(String(boolSWITCHTYPE));
     digitalWrite(ACTUATOR_ONOFF_PIN, boolSWITCHTYPE);
+    boolean result = client.publish(subjectGTWONOFFtoMQTT, datacallback);// we acknowledge the sending by publishing the value to an acknowledgement topic
+    if (result){
+      trc(F("MQTTtoONOFF ack pub."));
+      trc(String(datacallback));
+    }
   }
 }
 #endif
diff --git a/config_ONOFF.h b/config_ONOFF.h
index 3db2cc0..111f1cb 100644
--- a/config_ONOFF.h
+++ b/config_ONOFF.h
@@ -27,6 +27,7 @@
 /*----------------------------USER PARAMETERS-----------------------------*/
 /*-------------DEFINE YOUR MQTT PARAMETERS BELOW----------------*/
 #define subjectMQTTtoONOFF  Base_Topic Gateway_Name "/commands/MQTTtoONOFF"
+#define subjectGTWONOFFtoMQTT  Base_Topic Gateway_Name "/ONOFFtoMQTT"
 
 /*-------------------PIN DEFINITIONS----------------------*/
 #define ACTUATOR_ONOFF_PIN 4