Abstract: A data communication network is provided having a first communication device that includes a plurality of ports, and a control coupled to the ports and having a plurality of outputs extending from the control, with each of the outputs indicative of the status of one of the ports. The network further includes a power shut-off and recovery circuit coupled to the first communication device, and having a first signal detection circuit coupled to the ports for detecting activity on each port and for generating a first signal indicative of the activity, and a second signal detection circuit coupled to the outputs for detecting activity on each port and for generating a second signal indicative of the activity. The power shut-off and recovery circuit further includes a power control circuit that is coupled to the first and second signal detection circuits for receiving the first and second signals, respectively, and for selectively asserting an ENABLE signal based on either the first signal or the second signal.

Abstract: A power shut-off and recovery circuit for data communication devices is provided. The power shut-off and recovery circuit has a power control circuit for polling a plurality of ports. The power control circuit determines how many of the ports are in an operational mode and compares the number of active ports to a predetermined number of ports. If the number of active ports is less than the predetermined number of ports, the power control circuit de-asserts an ENABLE signal. If the number of active ports is greater than or equal to the predetermined number of ports, the power control circuit asserts the ENABLE signal. A source transfer circuit is provided for selectively disengaging the data communication device from a power source in response to the ENABLE signal. The power control circuit re-polls all the ports and updates the ENABLE signal accordingly.