The A-BUS hub is the core of the system. It distributes audio signal, system power, and status indication to A-BUS power
modules installed in rooms throughout the home and sends IR commands from the
power modules back to the source components.
It is usually located near the main
sound system (Amplifier/Receiver, CD, DVD, Tape, Cable, etc.). The HUB1x4 has 1 input and 4 zone outputs with an expansion port (IN/OUT) so multiple hubs can be
connected, to expand the system above 4 zones (PS included).