diff --git a/ReadMe.md b/ReadMe.md
index 0da37bc..b635c6c 100644
--- a/ReadMe.md
+++ b/ReadMe.md
@@ -37,4 +37,4 @@ Set the following parameter:
  * Base Topic
 
 
- ```docker run -e MQTT_SERVER="192.168.x.y" -e MQTT_TOPIC="testtopic/" sha256:```
+ ```docker run -t -i --device=/dev/ttyUSB0 -e SERIAL_DEVICE="/dev/ttyUSB0" -e MQTT_SERVER="192.168.x.y" -e MQTT_TOPIC="testtopic/" sha256:```
diff --git a/mqttclient/fanATserial2mqtt.py b/mqttclient/fanATserial2mqtt.py
index 44b808c..f5fc23d 100644
--- a/mqttclient/fanATserial2mqtt.py
+++ b/mqttclient/fanATserial2mqtt.py
@@ -3,8 +3,13 @@ import time
 import sys
 from paho.mqtt import client as mqtt_client
 import os
+import serial
+
+# MQTT Settings
 mqtt_server=os.environ['MQTT_SERVER']
 mqtt_topic=os.environ['MQTT_TOPIC']
+# SERIAL Port
+serial_device=os.environ['SERIAL_DEVICE']
 
 # The callback for when a PUBLISH message is received from the server.
 def on_message(client, userdata, msg):
@@ -27,6 +32,12 @@ val=0
 
 client.loop_start()
 
+ser = serial.Serial(serial_device, 115200, timeout=1)  # open serial port
+client.publish(mqtt_topic + "device", ser.name) # check which port was really used
+
+line = ser.readline()   # read a '\n' terminated line
+client.publish(mqtt_topic + "debug", line) # check which port was really used
+
 # Endless Loop
 while True:
     try: