A panel system includes a chassis holding one or more tray arrangements, which are each configured to receive one or more cassettes at two or more bays. The tray arrangements and cassettes cooperate to define a cassette sensor arrangement and a port occupancy sensor arrangement having separate interface points. The cassette sensor arrangement may include electronic memory storing physical layer information about the cassette. All active components of the port occupancy sensor arrangement are disposed on the tray while the electronic memories of the cassette sensor arrangement are stored on the cassettes.