Communication processor CP 343-1 for connecting SIMATIC S7-300 to Industrial Ethernet via ISO and TCP/IP, PROFINET IO controller or PROFINET IO device, integrated 2-port switch ERTEC 200, S7 communication, fetch/write, SEND/RECEIVE RFC1006, multicast, DHCP, NTC-CPU sync, with and without diagnostics, initialization via LAN, 2x RJ45 connection for LAN with 10/100 Mbit/s. Communication processor CP 343-1 for connecting SIMATIC S7-300 to Industrial Ethernet via ISO and TCP/IP, PROFINET IO controller or PROFINET IO device, integrated 2-port switch ERTEC 200, S7 communication, fetch/write, SEND/RECEIVE RFC1006, multicast, DHCP, NTC-CPU sync, with and without diagnostics, initialization via LAN, 2x RJ45 connection for LAN with 10/100 Mbit/s.