| 摘要 |
Signaling and coding methods and apparatus for long-range 10 and 100 mbps Ethernet transmission. In accordance with the method, a physical layer (PHY) device is provided that includes the long-range capabilities. In operation, the PHY measures the distance to a companion PHY, and if it is within the specification limits, communicates with the companion device in the normal way. If the distance is above the specification limits, the PHY checks to see if the companion PHY is similarly enabled, and if so, switches to a long-range signaling method. In a preferred embodiment, NRZ coding with pre-emphasis on the first bit of two or more bits of the same value is used for a first range exceeding the specification limit, and PAM4 coding is used for a second range exceeding the first range. Various embodiments are disclosed.
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