The Source Input Wallplate Module is designed to connect to an A-BUS Multi-Source
Audio Hub, which is the core of your A-BUS system. The Multi-Source Audio Hub will
accept up to four AUDZBX75 Source Input Modules to connect the Hub to a maximum
of four source components. It also repeats infrared (IR) commands to the source
components. The AUDZBX75 Source Input Module is activated by commands sent
from the AUDZ45 A-BUS Multisource Volume Control Module.