[realtek] Tx Status Questions (for RTL8139C)

[Donald Becker]

On Thu, 18 Apr 2002, Miao Qingjun wrote:
> What are the actual meanings of bits <Carrier Sense
> Lost> and <CD heart beat> of Tx Status of Tx Desc???
> And why they are set when Tx OK bit is set???

They make sense if you understand the physical layer signaling of
100baseTx, and how it evolved from coax-based Ethernet with external
tranceivers that provided "heartbeat" with a few invalid Rx bits at the
end of each transmit attempt.

-- 
Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
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