# Fundamentals

<figure><img src="https://2653492456-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FYV3zfJTXLR73Umqnex88%2Fuploads%2FcN6ZuovbmbYu3ZHFUwn6%2Fsmart%20home.png?alt=media&#x26;token=c0e47e2b-a1e7-4c38-aa53-b0429693e0f0" alt="" width="333"><figcaption></figcaption></figure>

Welcome to our engaging series of articles designed to clarify the world of the Internet of Things (IoT)! In this section we'll go back to the basics to understand some of the key concepts that makes IoT tick:

<table data-view="cards"><thead><tr><th></th><th></th><th></th></tr></thead><tbody><tr><td><a href="fundamentals/sim-cards">SIM cards </a></td><td><a href="fundamentals/ip-addresses">IP Addresses </a></td><td><a href="fundamentals/multi-imsi-vs-euicc">Multi-IMSI vs eUICC</a></td></tr><tr><td><a href="fundamentals/apn">APN</a> </td><td><a href="fundamentals/cell-id">Cell ID </a></td><td><a href="fundamentals/data-roaming">Data Roaming </a></td></tr><tr><td><a href="fundamentals/vpn">VPN</a> </td><td><a href="fundamentals/radio-access-technology">Radio Access Technology</a></td><td></td></tr></tbody></table>