A plurality of components are specified to perform a negotiation, where each component is a participant, a coordinator, or both. The oxide layer is deposited on an underlying substrate. The media access controller is configured to determine first and second qualities of the optical burst received by the first and second optical line terminals, respectively, and to determine an estimate of the transmitter wavelength based on the first quality and the second quality. Then, the emergency notification data is transmitted by radio to the emergency notification apparatus 70 along with an emergency notification signal.