One way to get wireless access to remotely located I/O is through a busable 900-MHz radio from Phoenix Contact’s Trusted Wireless Ethernet line. The RAD-ISM-900-EN-BUS radio lets users collect I/O without a remotely located PLC or I/O data concentrator. The bused I/O is made accessible to the network using a Modbus protocol. A multiple master function can create redundancy and wireless failover connections if a master or host radio is not accessible.