By Scott Gibson. With conventional wiring, you turn on the lights by flipping a wall-mounted switch that completes a 110-volt electrical circuit. But if you want to have the same switch activate a floor lamp at the other end of the room, or even several lights at the same time, your only recourse is to pull new cable and rewire the circuit.

In a programmable lighting control system, the wall switch is replaced with a keypad that can activate an overhead light, a receptacle for a floor lamp, or even a set of motor-driven window shades. A simple software change allows the same switch to control a completely different set of electrical lights or fixtures, all without rewiring.

The key to the system is separating the keypad from the 110-volt current. To do so, the keypad sends a message to a system controller over low-voltage Cat-5 cable. The system controller then tells a lighting controller to send current to the appropriate fixture or fixtures.

Programmable systems can activate carefully orchestrated lighting scenes. One might be a "dinner" setting, in which under-cabinet lights in the kitchen go to 10 percent of capacity, an over-the-table light in the dining room goes to 30 percent, and the over-sink fixture drops to zero. The system is easy to fine-tune, so light levels can be raised or lowered at any fixture, and new lighting scenes added as they are needed.

Equipment maker AMX in Richardson, Texas, ( says a sophisticated package like this one would start at about $10,000 for a house with a dozen lighting zones, not including installation.

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