US Patent 7319854 Automatic airplane seat location mapping

During a system reconfiguration, a selected column or column of wireless units, such as associated with airplane seats, are powered up. The first unit in the column detects a ground and begins a wireless identification process with an access point which allows the system to determine a corresponding physical location for each node's logical address. The first unit then closes a switch, which connects the ground to the next unit. As the next unit detects the ground on the line, such as a token line, the second unit communicates with the AP. This process continues sequentially down the column until the last unit is assigned a physical location/address. The next column of units can then be powered up and identified.