In ZigBee wireless networks, the distance between two PPM wireless units or between the control PC and a PPM wireless unit is allowed to extend. PPM router/repeater units can increase the distance between nodes in a ZigBee network. For example, if the distance between two nodes/wireless monitors is too large to establish communication, place one or more repeater units in between and the grid will form itself. The repeater unit has the same range parameters as the PPM wireless unit