Abstract: Switch for connecting field apparatuses and device for galvanically isolating at least one apparatus which is connectable to a 2-wire Ethernet bus system includes an uplink and a downlink PHY interface device that each have a transmitting unit and a receiving unit that has two output terminals for providing a received ternary-coded signal as differential signal, includes an uplink and a downlink signal split device that are each connected to the output terminals of an assigned receiving unit and are configured to split a ternary-coded signal provided as differential signal into two binary coded signals, and includes an uplink and a downlink optocoupler device that are each connected to an assigned signal split device and are configured to transfer two received binary-coded signals to a transmitting unit of an assigned PHY interface device.