COM20020_00 Datasheet, PDF (19/82 Pages) SMSC Corporation – Universal Local Area Network Controller with 2K x 8 On-Board RAM

A logic "0" is transmitted by the absence of the
dipulse. During reception, the 200nS dipulse
appearing on the media is coupled through the RF
transformer of the LAN Driver, which produces a
positive pulse at the RXIN pin of the COM20020.
The pulse on the RXIN pin represents a logic "1".
Lack of pulse represents a logic "0". Typically,
RXIN pulses occur at multiples of 400nS. The
COM20020 can tolerate distortion of plus or minus
100nS and still correctly capture and convert the
RXIN pulses to NRZ format. Figure 5 illustrates
the events which occur in transmission or
reception of data consisting of 1, 1, 0.
1 _{Please refer to TN7-5 – Cabling Guidelines for}
the COM20020 ULANC, available from SMSC, for
recommended cabling distance, termination, and
node count for ARCNET nodes.
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