This older device is pretty simple, it extends the network in your home using the houses power outlet wiring.
a) one SMC SMCHT-ETH is connected to your Internet (Modem, Access point etc.) and then plugged into a power outlet.
b) Other devices that want to use the internet also will need their own SMC SMCHT-ETH plugged into the wall and then the ethernet cable run to the device (PC or laptop etc.)
Obviously this isn't an ideal situation using one of these devices, but they still help computers that suffer wireless interference connect to the Internet at up to 85Mbps.
