| 摘要 |
The terminating impedance of a networked device in a wired communication channel is controlled to avoid an impedance discontinuity when power is applied and removed from the node or other event occurs that would change the impedance of the signal interface. When the node transmits or receives signals using the communication channel, the transmit or receive device presents a matched termination to the channel. When power is removed or the device is reset, the transmit and receive circuitry is not operational and the matched impedance is therefore maintained by a separate device. The impedance may be varied slowly from a match to a high impedance to allow other devices in the network to adapt to the change in multipath environment that results from the impedance change. Alternatively, the signal interface can be switched to a passive static impedance that is maintained while power is off or the disrupting event occurs.
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