To be used with all HFX kits. Home run wiring includes Power(2 wires) and Comm(2 wires). CAT-5 cable(4 pairs of 8 wires) are recommended. Star topology instate of daisy chain forsub-monitor expansion. Distance between main monitor and EX-PHUB is limited for main monitor needs more power to support doorbell and lock strike. Extra wires in some cases are needed for main monitor power transmission. Please contact technical support if necessary. Power : DC23V+/-l 0% (share power with Main Monitor's power adaptor). Power consumption : Standby