Advantech's Modbus Gateways with built-in Ethernet switches, the EKI-1221D and EKI-1222D provide transparent connectivity between Modbus (ASCII, RTU) serial devices and Ethernet based Modbus/TCP equipment. They are able to fulfill flexible installation and web browser configuration requirements for remote monitoring applications. The gateways have built-in Ethernet switches for cascading/daisy-chain connectivity that offers flexible cabling. Cascading connections support Ethernet auto-bypass to prevent accidental power failure in the event one of the Modbus Gateway's unexpectedly shuts down. They come with Windows utilities and web-based configuration, providing easier ways to set up. One port can be used to connect to the network, while the other can be used to connect to an Ethernet device or another EKI-1221D/1222D. They provide 921k baud speeds and are designed to fulfill any master/slave relationship. Moreover, they support 16 TCP masters, 16 TCP slaves, and each serial port supports up to 31 RTU/ASCII slave devices. They have built-in dual power inputs (12~48 Vdc) with one power fail relay output to detect power operation status and ensure reliable operation. They are built with thin DIN-rail mount form factors, IP30 metal housings, and Class I Division 2 certification for hazardous environment requirement.