Abstract: A buffer comprising a plurality of storage elements, a write pointer configured to indicate a particular storage element to write data received from an input data stream and a plurality of read pointers, each configured to indicate a particular data location to read data from to generate a number of output data streams. The input data stream and the output data streams may be part of a data communications device.

Abstract: An apparatus and method for testing a communication device using a loopback path. A circuit is used to internally generate a test packet and to check the test packet once the test packet is transmitted through a loopback path within the communication device. The loopback path includes a data path from a test transceiver, through a first path within the core logic, at least one selected physical transceiver, a second path within the core logic and back to the test transceiver.

Abstract: An expansion bus is provided for use with bus systems of the type wherein only a single data signal or data packet may be transmitted over the bus at any one time, such as Ethernet bus systems. The expansion bus includes a set of repeater units each connected to a set of local transceivers respectively connected to remote bus masters, such as remote computers. The repeater units are interconnected by a single data bus. Collision detection and arbitration of usage of the single data line is achieved using a distributed symmetric arbitration system as follows. Each repeater unit has a dedicated activity line which is interconnected to each of the other repeater units. Each repeater unit also includes an identical arbitration unit connected to the respective activity lines. When a repeater unit receives data from a local transceiver for transmission onto the single data bus, the arbitration unit of the repeater unit asserts an activity signal onto the corresponding activity line.