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Reverse Polarity Function
In the 10BASE-T mode, the PHY monitors for
receiver polarity reversal due to crossed wires
and corrects by reversing the signal internally.
Collision Detection Function
In the 10BASE-T mode, while in half duplex, a
collision state is indicated when there are
simultaneous transmissions and receptions on
the twisted pair link. During a collision state,
the nCOLL signal is asserted. If the received
data ends and the transmit control signal is still
active, the transmit data is sent to the MAC
within 9 bit times. The nnCOLL signal is de-
asserted within 9 bit times after the collision
terminates. In the AUI mode, the external
transceiver sends a 10MHz signal to the PHY
upon detection of a collision.
Link Integrity
The PHY test for a faulty twisted-pair link. In
the absence of transmit data, link test pulses
are tranmsitted every 16+/-18ms after the end
of the last transmission or link pulse on the
twisted pair medium. If neither valid data nor
link test pulses are received within 10 to 150ms,
the link is declared bad and both data
transmission as well as the operational
loopback function are disabled. The Link
Integrity function can be disabled for pre-
10BASE-T twisted-pair networks.