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12.3 Wiremap
While not required by IEEE 802.3-2004, Ethernet cable diagnostics are commonly used nowadays. This feature is
considered very important by the majority of the PHY vendors.
The feature provides extensive network and cable operating and status information:
• Cable length of properly terminated cable
• Cable termination mismatch, including short and open states
• Identification of which cable pair (A, B, C, D) is improperly terminated
• Coupling between cable pairs.
If a link is established in 10BASE-T or 100BASE-T mode, the unused cable pairs 4-5
and 7-8 are not tested.
Due to the legacy 10BASE-T hardware constraints, the cable length cannot be
reliably determined when the cable is connected to a remote PHY in 10BASE-T Half-
Duplex mode.
12.3.1 Fundamentals
The feature uses the internal DSP of the PHY that can analyze input signal characteristics in order to detect the link
quality.
The WIREMAP software suite compares the signal received at the PHY device to the link partner transmit signal
(defined by the standard) to determine the characteristics of the specific CAT 5/6 cable.
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