diff --git a/hass_button_emulator.py b/hass_button_emulator.py
index 9ec98c2..ef85604 100755
--- a/hass_button_emulator.py
+++ b/hass_button_emulator.py
@@ -2,33 +2,39 @@
 
 import time
 import paho.mqtt.client as mqtt
+import argparse
 import json
 
 import mqtt_client
 
 
-def on_connect(client, userdata, flags, reason_code, properties):
-    print(f"Connected: {reason_code}")
-    client.subscribe("#")
+def main():
+    parser = argparse.ArgumentParser(description="Allen & Heath Qu MQTT event emulator")
+    parser.add_argument("mqtt_hostname", help="IP of the MQTT broker")
+    args = parser.parse_args()
+
+    print(f"MQTT broker hostname: {args.mqtt_hostname}")
+
+    def on_connect(client, userdata, flags, reason_code, properties):
+        print(f"Connected: {reason_code}")
+        client.subscribe("#")
+
+    client = mqtt.Client(callback_api_version=mqtt.CallbackAPIVersion.VERSION2)
+    client.on_connect = on_connect
+
+    client.connect(args.mqtt_hostname, mqtt_client.MQTT_SERVER_PORT, 60)
+    client.loop_start()
+
+    j = json.dumps({"command": "scene_recall", "args": {"scene_id": 0}})
+    # j = json.dumps({'command': 'shutdown'})
+
+    client.publish(mqtt_client.MQTT_TOPIC, payload=j, qos=0, retain=False)
+
+    time.sleep(2)
+
+    client.loop_stop()
+    client.disconnect()
 
 
-def on_message(client, userdata, msg):
-    print(f"{msg.topic}: {msg.payload.decode()}")
-
-
-client = mqtt.Client(callback_api_version=mqtt.CallbackAPIVersion.VERSION2)
-client.on_connect = on_connect
-client.on_message = on_message
-
-client.connect(mqtt_client.MQTT_SERVER_ADDRESS, mqtt_client.MQTT_SERVER_PORT, 60)
-client.loop_start()
-
-j = json.dumps({"command": "scene_recall", "args": {"scene_id": 0}})
-# j = json.dumps({'command': 'shutdown'})
-
-client.publish(mqtt_client.MQTT_TOPIC, payload=j, qos=0, retain=False)
-
-time.sleep(2)
-
-client.loop_stop()
-client.disconnect()
+if __name__ == "__main__":
+    main()
diff --git a/mixer.py b/mixer.py
index 7ed3639..a5d7448 100755
--- a/mixer.py
+++ b/mixer.py
@@ -6,6 +6,9 @@ import mido
 
 from enum import Enum
 
+# For Allen & Heath Qu MIDI protocol documentation see:
+# https://www.allen-heath.com/content/uploads/2023/06/Qu_MIDI_Protocol_V1.9.pdf
+
 
 class Mixer:
     def __init__(self, ip):
diff --git a/mqtt_client.py b/mqtt_client.py
index 3ff7ed6..3b7e5b8 100644
--- a/mqtt_client.py
+++ b/mqtt_client.py
@@ -7,7 +7,6 @@ import paho.mqtt.client as mqtt
 import mixer
 from mixer import Mixer
 
-MQTT_SERVER_ADDRESS = "localhost"
 MQTT_SERVER_PORT = 1883
 MQTT_TOPIC = "homeassistant/device/mixer"
 
@@ -16,7 +15,7 @@ m: Mixer = None
 
 def on_connect(client, userdata, flags, reason_code, properties):
     print(f"Connected: {reason_code}")
-    client.subscribe("#")
+    client.subscribe(MQTT_TOPIC)
 
 
 def on_message(client, userdata, msg):
@@ -35,18 +34,20 @@ def on_message(client, userdata, msg):
 
 def main():
     parser = argparse.ArgumentParser(description="Allen & Heath Qu MQTT Remote Control")
-    parser.add_argument("ip", help="IP of the mixer")
+    parser.add_argument("mixer_ip", help="IP of the mixer")
+    parser.add_argument("mqtt_hostname", help="IP of the MQTT broker")
     args = parser.parse_args()
-    print(f"IP: {args.ip}")
+
+    print(f"Mixer IP: {args.mixer_ip}, MQTT broker hostname: {args.mqtt_hostname}")
 
     global m
-    m = mixer.Mixer(args.ip, mixer.MIXER_PORT)
+    m = mixer.Mixer(args.mixer_ip)
 
     client = mqtt.Client(callback_api_version=mqtt.CallbackAPIVersion.VERSION2)
     client.on_connect = on_connect
     client.on_message = on_message
 
-    client.connect(MQTT_SERVER_ADDRESS, MQTT_SERVER_PORT, 60)
+    client.connect(args.mqtt_hostname, MQTT_SERVER_PORT, 60)
     client.loop_forever()