diff --git a/source/components/device_tracker.thomson.markdown b/source/components/device_tracker.thomson.markdown
index ee36a4b3af8..9e65bde956d 100644
--- a/source/components/device_tracker.thomson.markdown
+++ b/source/components/device_tracker.thomson.markdown
@@ -23,4 +23,10 @@ device_tracker:
   password: YOUR_ADMIN_PASSWORD
 ```
 
+Configuration variables:
+
+- **host** (*Required*): The IP address of your router, eg. 192.168.1.1.
+- **username** (*Required*: The username of an user with administrative privileges, usually *admin*.
+- **password** (*Required*): The password for your given admin account.
+
 See the [device tracker component page](/components/device_tracker.html) for instructions how to configure the people to be tracked.