RAD128 is an intelligent, eight channel, 12-bit, analog-to-digital converter unit that interfaces to a host computer through an optoisolated asynchronous serial port. It is packaged in a steel enclosure for remote installation and input connections are via screw terminals on the card. Communication with the host computer is via EIA RS485 serial communications. ASCII-based command/response protocol permits communication with virtually any computer system that has an RS485 port. ASCII-based programming permits you to write applications in any high-level language that supports ASCII string functions. As many as 31 RAD128's may be connected on a single, two or four wire multidrop network. Each unit has a unique address and communication uses a master/slave protocol wherein the unit talks only if questioned by the computer.