The PT2001-A1 provides 2 Ethernet sockets at the rear of the housing. Always connect port A (ETH A) with an Ethernet switch.
A redundant Ethernet connection can be established by additionally connecting socket port B (ETH B) with an Ethernet switch. It can be the same switch or, for higher redundancy, another Ethernet switch in the system. If the connection on port A fails, the PT2001-A1 uses automatically port B for the communication.