Patent ID: 8244139

Claim:
A fiber optic data network implementing cascaded sub-networks, comprising: a primary sub-network including a primary optical line terminal communicatively coupled to a plurality of primary optical network units; a secondary sub-network including a secondary optical line terminal communicatively coupled to a plurality of secondary optical network units; and an intermediate optical network unit operatively connected in an upstream direction to the primary optical line terminal and in a downstream direction to the secondary optical line terminal to cascade the secondary sub-network with the primary sub-network operating via the intermediate optical network unit, wherein: the primary sub-network operates at a first data rate; the intermediate optical network unit operates at the first data rate; the secondary sub-network operates at a second data rate; the first data rate is greater than the second data rate, wherein the first data rate is at least three Megabits per second and the second data rate is no more than three hundred kilobits per second.