Patent ID: 8653935

Claim:
A method comprising: (a) in each of a plurality of intervals placing a receiver of a receiver unit into a receive mode, and then listening for a beacon during a predefined beacon slot time within the interval, and placing the receiver into a low-power sleep mode for substantially all the rest of the interval, wherein beacons are received by the receiver during the beacon slot times of some of the intervals but wherein no beacon is received during the beacon slot times of other of the intervals; (b) using the beacons received in (a) to synchronize the placing of the receiver into the receive mode with respect to the beacon slot times of the intervals; and (c) using a value in a field in one of the beacons to schedule a future initiation of an action by the receiver unit, wherein the action is scheduled to be initiated after said one beacon at a time when no beacon is being received, wherein (a), (b) and (c) are carried out by the receiver unit, wherein the receiver unit includes a transmitter, wherein the receiver unit does not transmit from its transmitter unless being first commanded to by a beacon that includes a command, wherein the action is a turning off of a fluorescent lamp, and wherein the receiver unit is a fluorescent lamp starter unit.