Relay Input/Output Module Relay Input/Output Module automatically inserts itself into the mix bus signal path leading to the power amplifier stage when installed. Features: Transformer-isolated, balanced line-level input, 600-ohm or 10k jumper selectable input impedance, 8-ohm, 750mW output, Input and output level controls, Relay responds to selectable priority level, External control of priority muting, N.O. or N.C. relay contacts, Input mutable by high priority modules with signal fade back, Output can gate relay priority level, Screw terminal strips, RJ11 connection with line output dedicated N.O. relay contact.