ETH-MODGW7xx series is a Modbus gateway that allows for a Modbus TCP / IP - UDP host to communicate with serial Modbus RTU / ASCII remote terminal units through an Ethernet network, thus eliminating the cable length limitation of legacy serial communication devices . The module can be used to create a pair-connection application (Pair-connection) as well as serial-bridge or serial-tunnel application) and can then route data over TCP / IP between two serial Modbus RTU / ASCII devices, is useful when connecting mainframe computers, servers or other serial devices using Modbus RTU / ASCII protocols and does not even have Ethernet capability. The maximum number of TCP connections for each serial port is up to 32 (RevB), this offers several Master access to slave devices on the same serial port. Read cache function is used to save previous requests and responses in the memory buffer in ETH-MODGW7xx. When other HMI / SCADA master controller sends the same requests to the same RTU slave device returns the cached answer immediately. This feature dramatically reduces the load on the serial
port communications and provides for faster TCP response, and improves the stability of the entire system.