diff --git a/docs/protocol.txt b/docs/protocol.txt
index 3c2c543..b1b5185 100644
--- a/docs/protocol.txt
+++ b/docs/protocol.txt
@@ -38,8 +38,10 @@ Types for controller:
 
     - 0 acknowledge valid message
       [ X B B B  B B B B ]
-          --------------
-             reserved
+          - - ----------
+          | ↓  reserved
+					↓ module ID
+	     type
 
     - 1 hello
       [ X B B B  B B B B ]
diff --git a/lib/obus_can.cpp b/lib/obus_can.cpp
index 3d851be..51b6b51 100644
--- a/lib/obus_can.cpp
+++ b/lib/obus_can.cpp
@@ -36,6 +36,7 @@ uint8_t payload_type(uint8_t module_type, uint8_t module_id, uint8_t msg_type) {
 	if (module_type == OBUS_TYPE_CONTROLLER && module_id == OBUS_CONTROLLER_ID) {
 		switch (msg_type) {
 			case OBUS_MSGTYPE_C_ACK:
+			  return OBUS_PAYLDTYPE_MODULEADDR;
 			case OBUS_MSGTYPE_C_HELLO:
 				return OBUS_PAYLDTYPE_EMPTY;
 
@@ -140,6 +141,16 @@ bool receive(struct message *msg) {
 				msg->infomessage.len = data_len;
 			}
 			break;
+		case OBUS_PAYLDTYPE_MODULEADDR:
+			{
+				if (receive_frame.can_dlc < 3) {
+					Serial.println(F("W Received illegal count msg: payload <3"));
+					return false;
+				}
+				msg->payload_address.type = receive_frame.data[1];
+				msg->payload_address.id = receive_frame.data[2];
+			}
+			break;
 		default:
 			Serial.println(F("W Couldn't determine payload type"));
 			return false;
@@ -194,6 +205,11 @@ void send(struct message *msg) {
 			length = msg->infomessage.len + 1;
 			break;
 
+		case OBUS_PAYLDTYPE_MODULEADDR:
+			send_frame.data[1] = msg->payload_address.type;
+			send_frame.data[2] = msg->payload_address.id;
+		break;
+
 		default:
 			Serial.print(F("E Unknown payload type "));
 			Serial.println(pyld_type);
diff --git a/lib/obus_can.h b/lib/obus_can.h
index a07574d..94f527a 100644
--- a/lib/obus_can.h
+++ b/lib/obus_can.h
@@ -35,6 +35,7 @@
 #define OBUS_PAYLDTYPE_GAMESTATUS 1
 #define OBUS_PAYLDTYPE_COUNT      2
 #define OBUS_PAYLDTYPE_INFO       3
+#define OBUS_PAYLDTYPE_MODULEADDR 4
 
 #define OBUS_PAYLD_INFO_MAXLEN (OBUS_MSG_LENGTH - 1)
 
@@ -66,6 +67,7 @@ struct message {
 		struct payld_gamestatus gamestatus;
 		uint8_t count;
 		struct payld_infomessage infomessage;
+		struct module payload_address;
 	};
 };