LattisLink 2800A 10BASE-T Workgroup Concentrator User’s Guide
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Appendix D Link Integrity Test Function
The Model 2800A 10BASE-T Workgroup Concentrator supports the IEEE
802.3i 10BASE-T Link Integrity Test Function on all its 10BASE-T ports. This
function monitors the UTP receive data wire-pair and determines the integrity
of the UTP link segment. The 10BASE-T transceiver located at the other end of
the link segment also monitors its UTP receive data wire-pair for link integrity.
Thus both data wire-pairs of the UTP link segment are tested for link integrity.
At all times the Model 2800A transmits either data or an idle signal, which is
called TP_IDL (twisted-pair idle signal). TP_IDL is transmitted in the absence
of data, and consists of a repeti-tive sequence of 100-nanosecond pulses
occurring every 16 milliseconds. The 100-nanosecond pulses are called Link
Test Pulses (LTPs).
All Model 2800A ports monitor their receive wire-pair for data and LTP
activity. If neither data nor LTPs are detected within 100 milliseconds, the
port's Link LED goes OFF to indicate no link status. While there is no link
integrity, the Model 2800A port does not send data to the UTP wire, and the
port receiver does not forward data from the UTP wire to the concentrator
backplane until link integrity is restored.
893-541-A D-1 Appendix D Link Integrity Test Function The Model 2800A 10BASE-T Workgroup Concentrator supports the IEEE 802.3i 10BASE-T Link Integrity Test Function on all its 10BASE-T ports.