The Sennheiser ADNPSKIT bundles the ADN PS power supply and the RMB2 rack mount kit. The ADN PS Power Supply allows the extension of the conference and discussion system to up to 400 conference units. It also increases the failure-safety of the system by allowing redundant ring-cabling (redundancy rings) on its two double conference ports. Up to 40 units can be connected in two rings and up to 70 units in alternative branch cabling (daisy-chain branches). Status LEDs at the front of the 19 in rack-mount unit indicate the type of cabling to easily monitor the system.