Ethernet I/O Module with 2 Ethernet Ports, 16-ch Wet Contact and Dry Contact Digital Input. Providing various digital I/O functions, the ET-2251 module is an IP-based Ethernet I/O monitoring and control module. The module can be remotely controlled through a 10/100 M Ethernet network by using Modbus TCP/UDP protocol. Modbus has become a de facto standard communications protocol in industry, and is now the most commonly available means of connecti..