Abstract: A fault diagnosis system is disclosed, including: a control unit, a first management board, a first pull-up unit, a second pull-up unit, a first pull-up switch, a second pull-up switch, and at least one central processing unit, the control unit is configured to receive physical partitioning information sent by the first management board, the first pull-up unit and the second pull-up unit are configured to pull up a fault indication signal of a fault diagnosis path to obtain a target signal, the first management board is configured to detect whether a level of the target signal is lower than a diagnosis threshold, and when the level of the target signal is lower than the diagnosis threshold, determine that a faulty central processing unit exists in the at least one central processing unit.

Abstract: In one aspect, the disclosure provides an HVAC system. In one embodiment, the HVAC system includes: (1) an air handler configured to condition and circulate air for the HVAC system, and (2) an air handler controller for the HVAC system configured to control operation of the air handler, the air handler controller including interface circuitry having a predetermined coupling impedance and configured to couple the air handler controller to components of the HVAC system via a communications network of the HVAC system, wherein a total of the predetermined coupling impedance and an end node coupling impedance at each of the components is substantially a defined maximum loading impedance for the communications network and wherein the end node coupling impedance of one of said plurality of end nodes is determined based on said predetermined coupling impedance and end node coupling impedances of remaining ones of the plurality of end nodes.

Abstract: A first communication apparatus 100 transmits a pilot signal which was generated by a pilot signal generation section 14, at predetermined timing, and detects an unbalance component of a transmission line 300 at the time of pilot signal transmission in an unbalance component detection section 13, and controls a transmission signal in such a manner that an unbalance component is reduced by a transmission control section 12 on the basis of the detected unbalance component.

Abstract: Power line communication (PLC) systems are presented for connecting dimming switches with electronic ballasts for driving compact fluorescent lamps and other applications using a power distribution network, including a transmitter and a receiver connected in a series circuit for transmission of multi-bit data, where the receiver has a load control circuit for selectively adjusting the receiver loading and to sense current interruptions to provide a data output.