The Barionet 400 is a programmable I/O device server based on Linux and OpenWRT. It provides one 10/100 Ethernet interface with IPv4 and IPv6 support, 2.4 GHz Wi-Fi, four relay outputs rated at 30 V DC and 0.5 A, four dry-contact digital inputs, and one USB host interface. The unit supports web-based configuration, HTTP and SNMP communication, and programming in C plus plus, Lua, or Python. It operates from 9 to 30 V DC or IEEE 802.3af PoE.