The box allows the number of controllers that will be connected to the matrix to be multiplied. It allows to deport the connections by connecting the controllers in star when the connection to the chain is not possible. RD IN port: to connect to the matrix. RD EXP ports (1 audio): RD connection for DZ-MICDESK / DZ-CTL2OUT and DZ-BOX22 (remote audio data transport and control devices). 2/3/4 Control: RD connections for DZ-CTL / DZ-CTL2OUT (remote device control data only) / DZ-PAD Power supply: If several controllers are connected or if the distance between the interfaces is large, it will be necessary to supply the box with 24 V DC. Use shielded CAT5e or CAT6 cable with a maximum length of 100 m between each device. LINK FOR FULL INFORMATION: DZ-EXPAND