diff --git a/source/_components/sensor.fritzbox_callmonitor.markdown b/source/_components/sensor.fritzbox_callmonitor.markdown
index dd57677a9ca..6e50df044b1 100644
--- a/source/_components/sensor.fritzbox_callmonitor.markdown
+++ b/source/_components/sensor.fritzbox_callmonitor.markdown
@@ -17,10 +17,22 @@ ha_iot_class: "Local Polling"
 The `fritzbox_callmonitor` sensor monitors the call monitor exposed by [AVM Fritz!Box](http://avm.de/produkte/fritzbox/) routers on TCP port 1012. It will assume the values `idle`, `ringing`, `dialing` or `talking` with the phone numbers involved contained in the state attributes.
 It can also access the internal phone book of the router to look up the names corresponding to the phone numbers and store them in the state attributes.
 
-## {% linkable_title Configuration %}
+## {% linkable_title Prerequisites %}
+
+To build the package you have to install some dependencies first.
+
+```bash
+$ sudo apt-get update
+$ sudo apt-get install libxml2-dev libxslt-dev \
+  python3-setuptools zlib1g-dev build-essential
+```
+
+## {% linkable_title Setup%}
 
 To activate the call monitor on your Fritz!Box, dial #96\*5\* from any phone connected to it.
 
+## {% linkable_title Configuration %}
+
 To use the Fritz!Box call monitor in your installation, add the following to your `configuration.yaml` file:
 
 ```yaml