Abstract: A line powering system for a multi-channel communication system is disclosed having a central office or primary communication terminal configured to communicate with one or more remote locations via two or more communication lines. Line powering, from the primary location to the remote location, is provided by a power supply, which is selectively connected to one or more of the lines via a switching module. Line monitoring and switch control may occur automatically or by a controller. A ground fault detector is provided to monitor for excessive ground fault current and selectively disconnect the faulted line. A rapid line voltage discharge module is provided to discharge line voltage to meet specification.

Abstract: The present invention teaches a variety of timing generation and recovery schemes for providing high precision clock synchronization in cascaded communications systems where each point of communication has a unique clock. To accomplish the high precision, one embodiment of the present invention teaches quantizing information related to phase relation between a master clock at the transmitter and a network link clock. This quantized phase information can be transmitted with very little bandwidth, recovered and the receiver and used to recover the timing information with high precision.

Abstract: A noise cancellation system configured to isolate and process a common mode noise signal to generate a cancellation signal. The cancellation signal is combined with a differential signal to cancel unwanted differential mode noise that coupled onto the differential signal. In one embodiment a multi-channel communication system utilizes two or more channels that are in close proximity to other alien channels. A common mode signal isolation unit is configured to isolate common mode noise. The common mode noise signal is processed with a filter or other means to generate a cancellation signal. The cancellation signal is combined with the differential signal to thereby cancel noise that coupled onto the differential signal. The processed common mode noise signal may be made to approximate the differential mode noise signal. The common mode signal may be obtained from a center tap of a transformer, or a sensing winding of a three winding transformer.