Ethernet FOIRL, 10BASE-FL, and 10BASE-FB

Manchester encoding also is used for 10Mbps Ethernet across fiber optic cable. However, some special signals have been added to the fiber optic specifications to support some useful features.

As noted in Chapter 6, "The Ethernet 10Mbps Physical Layer," whenever data is not being transmitted by a FOIRL or 10BASE-FL interface, the interface sends special idle pulses onto the send fiber.

The idle signal for 10BASE-FB is called a synchronous idle and is made up of special clocked symbols. Two new Manchester symbols are defined:

  • Manchester Code Violation Zero (MV0) A clocked symbol that is low for a bit duration.

  • Manchester Code Violation One (MV1) A clocked symbol that is high for a bit duration.

A synchronous ...

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