“IoT Security” is a broad phrase. So broad as to arguably be meaningless in its own right. So, to open, we need to define the scope and purpose of this article to position it clearly in the IoT hierarchy. This article introduces some of the security concepts associated with deploying cellular (3G/4G) routers + Gateways such as those sold by Robustel and other manufacturers around the world. The architecture of such deployments typically involves a router, a SIM card and a connected device such as a PLC, IP Camera, BMS Controller, media player or other similar device at the edge, using publicly available cellular networks to move data from the edge to the cloud. Data and the infrastructure itself can be vulnerable to malicious behaviour and this article takes a practical view on the general and Robustel-specific solutions to these “IoT Security” challenges.