DUAL-BAND LINE INTERFACE CIRCUIT CAPABLE OF MULTI-BAND COMMUNICATION

In an embodiment, a DSL communication device comprising a line interface circuit is disclosed. The line interface circuit includes a hybrid circuit to interface the communication device to a communication line, a lowpass transmit filter to pass signals in a first frequency band, and a highpass transmit filter to pass signals in a second frequency band, where the second frequency band is higher in frequency than the first frequency band. The outputs of the highpass and lowpass filters are coupled in parallel to the communication line. The lowpass and highpass filters as well as the low and highpass transformers are optimized for their frequency bands. Further, the edges of the low and high frequency bands are sufficiently separated to reduce interference from the other frequency band. These factors, in part, allow a multiple tone communication device to be capable of operating in multiple modes of operation with multiple DSL varieties.