Abstract: The invention relates to the efficient coding of packetized binary (NRZ) data, for example Ethernet packets, over a binary channel. Since Ethernet packetized data has three states (0, 1, and Idle), the theoretical bandwidth required for transmission, assuming completely random packets of arbitrary length and arbitrary interpacket idle periods, i.e. gaps, is 1.585 the data rate. The invention uses the information that both packets and gaps have predetermined minimum lengths constructs more efficient codes. In particular, a coding scheme is shown that provides in two states signal requiring a bandwidth of only 1.25 the three state signal data rate.

Abstract: A fault tolerant power supply system includes a plurality of devices coupled to a common power distribution bus. The devices are arranged and connected in a hierarchical order. The system provides that the devices of higher rank or position in the hierarchy to obtain priority in drawing power from the bus. Each device is coupled to the next adjacent device via a control status line that indicates whether there has been a failure of the power supply of any device higher up in the hierarchy. In the event that the local power supply of a device fails, it can be selectively connected to the power distribution bus to draw power, only if the control status line indicates that there have no failures in the devices having a higher hierarchical rank. Once connected to power distribution bus, if a higher ranking device should experience a power supply failure, the device will be disconnected from the power distribution bus and the higher ranking device connected to the power distribution bus.

Abstract: A port switching hub consists of a number of local area network ports, a number of internal channels to which these ports may be connected from time to time under program control, and circuitry suitable for causing each channel to function as a local area network repeater. The ports have a variety of control and measurement functions associated with them. An instrumentation, a programmable controller or embedded computer program, for example, estimates the traffic load on each channel based on information available from the port controllers. The control program further predicts the effect of reassigning the ports to different channels based on available data, internal models of network behavior, and other constraints such as address assignment, and changes the port assignment so as to achieve a goal, such as balancing of traffic load or assignment. The reassignment of ports may occur periodically, or in response to an event, and may or may not be forced to occur during a period of channel inactivity.