| 摘要 |
A method and apparatus for transmitting and receiving information over a network that allows the detection of data transmission activity over a wire pair on the network. Within a computer system or other network device a driver-receiver circuit along with an activity detector circuit are coupled to the wire pair such that when the wire pair is inactive, an Inactive signal is asserted, and the activity detector circuit will notify the network device that the network is not currently transmitting data. The activity detector includes a first voltage comparator coupled to a first differential threshold voltage generator and a second voltage comparator coupled to a second differential threshold voltage generator. The absolute value of voltages generated by both differential threshold voltage generators is less than the minimum voltage levels required for a valid signal to be placed on the wire pair, The outputs of the first and second voltage comparators are coupled to an AND gate such that when the voltage differential across the wire pair is not sufficiently high to be a valid logic 1 or a valid logic 0, an Inactive signal is asserted. The Inactive signal, which indicates that the network is not currently transmitting data, is detected by the network device in which the driver-receiver circuit is incorporated.
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