Abstract: A system and method for transmitting data streams subject to crosstalk, in which an adjustable parameter, preferably data rate, is adjusted using feedback of performance characteristics, preferably signal-to-noise ratio (SNR) and line attenuation, maximizing total throughput of the data streams. The invention is particularly applicable to inverse multiplex (IMUX) systems, where total throughput is more important than the throughput of any individual data stream.

Abstract: Network access apparatus includes first and second master units, each having a physical interface to a packet-switched network. A plurality of slave units, each slave unit having one or more ports to respective subscriber lines, are linked by a plurality of physical interface lines in one or more daisy chains, in which the slave units are mutually connected in series by the physical interface lines therebetween. Each daisy chain includes at least a first slave unit connected by one of the physical interface lines to the first master unit and a last slave unit connected by another of the physical interface lines to the second master unit.