EtherNet/IP protocol communication has been added to the Protos X line of field I/O. The "Xpansion" field modular I/O system consists of a bus coupler and its associated input/output terminals. Both two- to 12-point discrete I/O terminals and two- to eight-channel analog I/O terminals are available. Up to 64 terminals per assembly and 255 I/O terminals total are possible. Modbus and EtherNet/IP bus couplers provide connection options to hundreds of industrial control devices. The PX-TCP1 and PX-TCP2 server bus couplers offer Modbus TCP protocol over Ethernet. The PX-MOD slave bus coupler uses Modbus RTU/ASCII protocol over RS-485. The PX-EIP1 server bus coupler uses EtherNet/IP protocol over Ethernet.