The RS8-R is a Relay switching unit with 8 inputs for connection of 8 amplifiers, 2 inputs for connecting the back-up amplifiers and 8 output lines. The 8 output lines are normally connected directly to the inputs, so to the outputs the primary amplifiers. In case of failure on an amplifier, through serial commands or logic inputs, you can disconnect the line of this amplifier and connect it to the backup amplifier.