Abstract: A technique to identify a response cell in a ranging grant procedure is disclosed herein. The format of the response cell reduces the probability of erroneous response cell detection. The response cell is a conventional ATM cell whose payload includes multiple cell delineation bytes (CDBs).

Abstract: A system and method for enabling an optical network unit (ONU) in a passive optical network to scramble data and send the scrambled data upstream to an optical line termination unit (OLT). In passive optical networks the clocks in the OLT and ONU are synchronized by recovering the clock from the data signal. However, the clocks may drift when no data transitions occur on a long string of data. In addition, the OLT may require data transitions to ensure proper adjusting of its receive threshold. In either circumstance, collectively called Loss of Synchronization, the data may not be received correctly by the receiver and the transmitter will need to resend the data. In the present invention, the transmitter will vary the seed used in the scrambling operation. The use of a different seed per each transmission significantly reduces the chances that a loss of synchronization will occur.