Abstract: A communication unit, coupled to a communication link, may be enabled if a signal is present on the communication link and the unit is active. However, if no signal is present on the communication link, the communication unit generates a token used to activate another communication unit coupled to another communication link. This token may be generated after a delay which allows the communication unit to wait some time for the signal to appear on the communication link before generating the token. Where a communication unit has been activated and enabled, that communication unit may receive signals from the communication link or transmit signals onto the communication link. Selecting a first communication unit from a number of communication units to be activated may be accomplished by coupling one of the communication units to a start-up circuit. The start-up circuit provides a start-up token to activate the first communication unit.

Abstract: A multi-port network interface device including a transmit data bus; a receive data bus; a medium access controller (MAC) and physical signaling (PLS) circuit, coupled to the transmit and receive data buses, and configured to interface to a network layer; at least one transmitter, coupled to the transmit data bus, and configured to transmit data to a physical layer; at least one receiver, coupled to the receive data bus, and configured to receive data from the physical layer; a local collision detector, coupled to the transmit and receive data buses, and configured to detect local collisions on the physical layer; a near end collision detector, coupled to the receive data bus, and configured to detect near end collisions on the physical layer; and a jabber detector, coupled to the transmit data bus, and configured to monitor a length of data transmissions.