diff --git a/df_datalink_sp/src/system_monitor.c b/df_datalink_sp/src/system_monitor.c
index b7a1046..633b97b 100644
--- a/df_datalink_sp/src/system_monitor.c
+++ b/df_datalink_sp/src/system_monitor.c
@@ -210,6 +210,7 @@ void SysMonitor_UpdateSendPayloadFLJRaw(uint8_t *buff)
 	buffIndx = GetWritable(sysMonitorInst->sendPLCtrl);
 	sysMonitorInst->sendPLCtrl.wBusy = buffIndx;
 	memcpy(sysMonitorInst->sendPL[buffIndx].data_flj, buff, sizeof(uint8_t) * PAYLOAD_FLJ);
+	sysMonitorInst->sendPL[buffIndx].dataId_flj++;
 	sysMonitorInst->sendPLCtrl.latest = buffIndx;
 	sysMonitorInst->sendPLCtrl.wBusy = BUFF_NONE;
 }
@@ -217,7 +218,7 @@ void SysMonitor_UpdateSendPayloadFLJRaw(uint8_t *buff)
 /**
  * Get send FLJ payload as raw data.
  */
-void SysMonitor_GetSendPayloadFLJRaw(uint8_t *buff)
+void SysMonitor_GetSendPayloadFLJRaw(uint8_t *buff, uint32_t *id)
 {
 	ASSERT(sysMonitorInst != NULL);
 	uint8_t buffIndx, buffIndex_old;
@@ -227,7 +228,11 @@ void SysMonitor_GetSendPayloadFLJRaw(uint8_t *buff)
 	else
 		buffIndx = GetReadable(sysMonitorInst->sendPLCtrl);
 	sysMonitorInst->sendPLCtrl.rBusy = buffIndx;
-	memcpy(buff, sysMonitorInst->sendPL[buffIndx].data_flj, sizeof(uint8_t) * PAYLOAD_FLJ);
+	if (sysMonitorInst->sendPL[buffIndx].dataId_flj != DATA_ID_NONE)
+	{
+		memcpy(buff, sysMonitorInst->sendPL[buffIndx].data_flj, sizeof(uint8_t) * PAYLOAD_FLJ);
+	}
+	*id = sysMonitorInst->sendPL[buffIndx].dataId_flj;
 	sysMonitorInst->sendPLCtrl.rBusy = buffIndex_old;
 }
 
@@ -241,6 +246,7 @@ void SysMonitor_UpdateSendPayloadLJRaw(uint8_t *buff)
 	buffIndx = GetWritable(sysMonitorInst->sendPLCtrl);
 	sysMonitorInst->sendPLCtrl.wBusy = buffIndx;
 	memcpy(sysMonitorInst->sendPL[buffIndx].data_lj, buff, sizeof(uint8_t) * PAYLOAD_LJ);
+	sysMonitorInst->sendPL[buffIndx].dataId_lj++;
 	sysMonitorInst->sendPLCtrl.latest = buffIndx;
 	sysMonitorInst->sendPLCtrl.wBusy = BUFF_NONE;
 }
@@ -248,7 +254,7 @@ void SysMonitor_UpdateSendPayloadLJRaw(uint8_t *buff)
 /**
  * Get send LJ payload as raw data.
  */
-void SysMonitor_GetSendPayloadLJRaw(uint8_t *buff)
+void SysMonitor_GetSendPayloadLJRaw(uint8_t *buff, uint32_t *id)
 {
 	ASSERT(sysMonitorInst != NULL);
 	uint8_t buffIndx, buffIndex_old;
@@ -258,7 +264,11 @@ void SysMonitor_GetSendPayloadLJRaw(uint8_t *buff)
 	else
 		buffIndx = GetReadable(sysMonitorInst->sendPLCtrl);
 	sysMonitorInst->sendPLCtrl.rBusy = buffIndx;
-	memcpy(buff, sysMonitorInst->sendPL[buffIndx].data_lj, sizeof(uint8_t) * PAYLOAD_LJ);
+	if (sysMonitorInst->sendPL[buffIndx].dataId_lj != DATA_ID_NONE) 
+	{
+		memcpy(buff, sysMonitorInst->sendPL[buffIndx].data_lj, sizeof(uint8_t) * PAYLOAD_LJ);
+	}
+	*id = sysMonitorInst->sendPL[buffIndx].dataId_lj;
 	sysMonitorInst->sendPLCtrl.rBusy = buffIndex_old;
 }
 
@@ -273,6 +283,7 @@ void SysMonitor_UpdateRecvPayloadFLJRaw(uint8_t *buff)
 	buffIndx = GetWritable(sysMonitorInst->recvPLCtrl);
 	sysMonitorInst->recvPLCtrl.wBusy = buffIndx;
 	memcpy(sysMonitorInst->recvPL[buffIndx].data_flj, buff, sizeof(uint8_t) * PAYLOAD_FLJ);
+	sysMonitorInst->recvPL[buffIndx].dataId_flj++;
 	sysMonitorInst->recvPLCtrl.latest = buffIndx;
 	sysMonitorInst->recvPLCtrl.wBusy = BUFF_NONE;
 }
@@ -280,7 +291,7 @@ void SysMonitor_UpdateRecvPayloadFLJRaw(uint8_t *buff)
 /**
  * Get send FLJ payload as raw data.
  */
-void SysMonitor_GetRecvPayloadFLJRaw(uint8_t *buff)
+void SysMonitor_GetRecvPayloadFLJRaw(uint8_t *buff, uint32_t *id)
 {
 	ASSERT(sysMonitorInst != NULL);
 	uint8_t buffIndx, buffIndex_old;
@@ -290,7 +301,11 @@ void SysMonitor_GetRecvPayloadFLJRaw(uint8_t *buff)
 	else
 		buffIndx = GetReadable(sysMonitorInst->recvPLCtrl);
 	sysMonitorInst->recvPLCtrl.rBusy = buffIndx;
-	memcpy(buff, sysMonitorInst->recvPL[buffIndx].data_flj, sizeof(uint8_t) * PAYLOAD_FLJ);
+	if (sysMonitorInst->recvPL[buffIndx].dataId_flj != DATA_ID_NONE)
+	{
+		memcpy(buff, sysMonitorInst->recvPL[buffIndx].data_flj, sizeof(uint8_t) * PAYLOAD_FLJ);
+	}
+	*id = sysMonitorInst->recvPL[buffIndx].dataId_flj;
 	sysMonitorInst->recvPLCtrl.rBusy = buffIndex_old;
 }
 
@@ -304,6 +319,7 @@ void SysMonitor_UpdateRecvPayloadLJRaw(uint8_t *buff)
 	buffIndx = GetWritable(sysMonitorInst->recvPLCtrl);
 	sysMonitorInst->recvPLCtrl.wBusy = buffIndx;
 	memcpy(sysMonitorInst->recvPL[buffIndx].data_lj, buff, sizeof(uint8_t) * PAYLOAD_LJ);
+	sysMonitorInst->recvPL[buffIndx].dataId_lj++;
 	sysMonitorInst->recvPLCtrl.latest = buffIndx;
 	sysMonitorInst->recvPLCtrl.wBusy = BUFF_NONE;
 }
@@ -311,7 +327,7 @@ void SysMonitor_UpdateRecvPayloadLJRaw(uint8_t *buff)
 /**
  * Get send LJ payload as raw data.
  */
-void SysMonitor_GetRecvPayloadLJRaw(uint8_t *buff)
+void SysMonitor_GetRecvPayloadLJRaw(uint8_t *buff, uint32_t *id)
 {
 	ASSERT(sysMonitorInst != NULL);
 	uint8_t buffIndx, buffIndex_old;
@@ -321,7 +337,11 @@ void SysMonitor_GetRecvPayloadLJRaw(uint8_t *buff)
 	else
 		buffIndx = GetReadable(sysMonitorInst->recvPLCtrl);
 	sysMonitorInst->recvPLCtrl.rBusy = buffIndx;
-	memcpy(buff, sysMonitorInst->recvPL[buffIndx].data_lj, sizeof(uint8_t) * PAYLOAD_LJ);
+	if (sysMonitorInst->recvPL[buffIndx].dataId_lj != DATA_ID_NONE) 
+	{
+		memcpy(buff, sysMonitorInst->recvPL[buffIndx].data_lj, sizeof(uint8_t) * PAYLOAD_LJ);
+	}
+	*id = sysMonitorInst->recvPL[buffIndx].dataId_lj;
 	sysMonitorInst->recvPLCtrl.rBusy = buffIndex_old;
 }
 
diff --git a/df_datalink_sp/src/system_monitor.h b/df_datalink_sp/src/system_monitor.h
index 9a43985..a29a395 100644
--- a/df_datalink_sp/src/system_monitor.h
+++ b/df_datalink_sp/src/system_monitor.h
@@ -7,6 +7,8 @@
 #define PAYLOAD_FLJ 78
 #define PAYLOAD_LJ 168
 
+#define DATA_ID_NONE UINT32_MAX
+
 typedef struct
 {
 	// FIXME: To Complete
@@ -54,7 +56,9 @@ typedef struct
 
 typedef struct
 {
+	uint32_t dataId_lj;
 	uint8_t data_lj[PAYLOAD_LJ];
+	uint32_t dataId_flj;
 	uint8_t data_flj[PAYLOAD_FLJ];
 } PAYLOAD;
 
@@ -131,10 +135,10 @@ void SysMonitor_UpdateSendPayloadFLJRaw(uint8_t *buff);
 void SysMonitor_UpdateRecvPayloadFLJRaw(uint8_t *buff);
 void SysMonitor_UpdateSendPayloadLJRaw(uint8_t *buff);
 void SysMonitor_UpdateRecvPayloadLJRaw(uint8_t *buff);
-void SysMonitor_GetSendPayloadFLJRaw(uint8_t *buff);
-void SysMonitor_GetRecvPayloadFLJRaw(uint8_t *buff);
-void SysMonitor_GetSendPayloadLJRaw(uint8_t *buff);
-void SysMonitor_GetRecvPayloadLJRaw(uint8_t *buff);
+void SysMonitor_GetSendPayloadFLJRaw(uint8_t *buff, uint32_t *id);
+void SysMonitor_GetRecvPayloadFLJRaw(uint8_t *buff, uint32_t *id);
+void SysMonitor_GetSendPayloadLJRaw(uint8_t *buff, uint32_t *id);
+void SysMonitor_GetRecvPayloadLJRaw(uint8_t *buff, uint32_t *id);
 
 void SysMonitor_UpdateSendSlotLog(SLOTLOG *log);
 void SysMonitor_UpdateRecvSlotLog(SLOTLOG *log);