Switches are devices that distribute an Ethernet or PROFINET network along a machine or throughout the shop floor. They can connect PLCs with HMI panels, or PLCs with remote peripherals. They enable many other devices to be connected, and can be used to create various topologies.
Compared to standard switches, they're much more resistant to surrounding conditions. They can operate in changing temperatures with ease, are resistant to electromagnetic interference from other devices (e.g. frequency inverters, etc.), and are equipped with rugged steel cases. Finally, industrial switches boast a dual power input system. When one power supply fails to work, the other one takes over and keeps powering the switch.