What type of devices would not commonly be considered part of the IoT device layer?

The correct answer, non-connected appliances, signifies devices that do not have the capability to connect to the internet or communicate with other devices. The Internet of Things (IoT) primarily consists of devices that can send and receive data, allowing them to be monitored and controlled remotely. Non-connected appliances lack this technology, rendering them unable to participate in the IoT framework.

In contrast, networking gear, mobile devices, and sensors are integral components of the IoT device layer. Networking gear, such as routers and switches, facilitates connectivity between IoT devices and the internet. Mobile devices enable users to interact with IoT systems while on the go. Sensors, often embedded within IoT devices, gather data from their environment to enhance functionality and provide information for analysis. Each of these categories actively contributes to the interconnected nature of IoT systems, unlike non-connected appliances, which stand apart due to their lack of connectivity.