1. Connect a device, such as a computer or tablet, to the internet through WiFi or using an Ethernet cable connected to your modem.
2. Open a web browser and type http://192.168.0.1 into the web address field.
3. Log in to the modem's online user interface (Modem GUI) using your Administrator Username and Administrator Password. Unless you have changed the default settings, you can find this information on the modem's sticker. Note that these are different from your wireless SSID and security key.
4. Select "Utilities."
5. Select "Wireless Diagnostics" in the left sidebar.
6. Select a Wireless Tool from the dropdown menu. The list of diagnostic tools varies from model to model, so your particular router may not offer all of the options listed below. Click on the tool name to view a sample.