diff --git a/tasmota/xsns_53_sml.ino b/tasmota/xsns_53_sml.ino
index 900558b6b..25a6b81a6 100755
--- a/tasmota/xsns_53_sml.ino
+++ b/tasmota/xsns_53_sml.ino
@@ -1041,6 +1041,9 @@ void ADS1115_init(void) {
 char sml_start;
 uint8_t dump2log=0;
 
+uint8_t ser_act_LED_pin=255;
+uint8_t ser_act_meter_num=0;
+
 #define SML_SAVAILABLE Serial_available()
 #define SML_SREAD Serial_read()
 #define SML_SPEAK Serial_peek()
@@ -1623,6 +1626,9 @@ uint32_t meters;
       if (meter_desc_p[meters].type != 'c') {
         // poll for serial input
         if (!meter_ss[meters]) continue;
+        if (ser_act_LED_pin!=255 && (ser_act_meter_num==0 || ser_act_meter_num-1==meters)) {
+          digitalWrite(ser_act_LED_pin, meter_ss[meters]->available() && !digitalRead(ser_act_LED_pin)); // Invert LED, if queue is continuously full
+        }
         while (meter_ss[meters]->available()) {
           sml_shift_in(meters, 0);
         }
@@ -3253,9 +3259,11 @@ uint8_t parity=0;
 
 // dump to log shows serial data on console
 // has to be off for normal use
-// in console sensor53 d1,d2,d3 .. or. d0 for normal use
+// in console sensor53 d1, d2, d3 ... or d0 for normal use
 // set counter => sensor53 c1 xxxx
 // restart driver => sensor53 r
+// meter number for monitoring serial activity => sensor53 m1, m2, m3 ... or m0 for all (default)
+// LED-GPIO for monitoring serial activity => sensor53 l2, l13, l15 ... or l255 for turn off (default)
 
 bool XSNS_53_cmd(void) {
   bool serviced = true;
@@ -3272,7 +3280,7 @@ bool XSNS_53_cmd(void) {
         dump2log=index;
         ResponseTime_P(PSTR(",\"SML\":{\"CMD\":\"dump: %d\"}}"),dump2log);
       } else if (*cp=='c') {
-          // set ounter
+        // set counter
           cp++;
           uint8_t index=*cp&7;
           if (index<1 || index>MAX_COUNTERS) index=1;
@@ -3296,6 +3304,27 @@ bool XSNS_53_cmd(void) {
         ResponseTime_P(PSTR(",\"SML\":{\"CMD\":\"restart\"}}"));
         SML_CounterSaveState();
         SML_Init();
+      } else if (*cp=='m') {
+        // meter number for serial activity
+        cp++;
+        if (!isdigit(*cp)) {
+          ResponseTime_P(PSTR(",\"SML\":{\"CMD\":\"ser_act_meter_num: %d\"}}"),ser_act_meter_num);
+        } else {
+          ser_act_meter_num=atoi(cp);
+          ResponseTime_P(PSTR(",\"SML\":{\"CMD\":\"ser_act_meter_num: %d\"}}"),ser_act_meter_num);
+        }
+      } else if (*cp=='l') {
+        // serial activity LED-GPIO
+        cp++;
+        if (!isdigit(*cp)) {
+          ResponseTime_P(PSTR(",\"SML\":{\"CMD\":\"ser_act_LED_pin: %d\"}}"),ser_act_LED_pin);
+        } else {
+          ser_act_LED_pin=atoi(cp);
+          if (ser_act_LED_pin!=255) {
+            pinMode(ser_act_LED_pin, OUTPUT);
+          }
+          ResponseTime_P(PSTR(",\"SML\":{\"CMD\":\"ser_act_LED_pin: %d\"}}"),ser_act_LED_pin);
+        }
       } else {
         serviced=false;
       }