Albedo xGenius - Connecting the Tester

Cable Tests
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is connected with a remote MDIX port through an straight cable and that an MDI (or
MDIX) port is connected to a second MDI (or MDIX) port through a crossover cable.
The advantage of this procedure is that there is no need to think about which cable
(crossover or straight) is required for interconnection of network equipment and
stations. However, if you need to know the way the cable is wired, then it is mandatory
to know the MDI / MDIX status of the near and far ends.
3.1.2. Connecting the Tester
Cable testing with the Ethernet cable test mode is different to the other modes because
in this case the test equipment does not generate any digital framed or unframed
signal. It relies on the remote end to supply some information about the wiring and other
metrics related with the physical transmission medium. The amount of information to
be supplied depends on the communications interface. It is not the same for Gigabit
Ethernet than for Fast Ethernet interfaces. If there is no link from the remote end, the
equipment attempts to find out the reason (short circuit, open circuit...).
The cable test is available for Port A only. The Port B could be used as an auxiliary port
to determine whether a cable is straight or crossover. Cable tests can only run from the
native RJ-45 interfaces, they are not available through electric SFP modules.
The best way to run the cable test is to connect the cable under test between port A
and port B. You can use other test configurations like a connection between Port A and
a switch but in this case you will be unable to get all the information from the cable. Here
you have some details about the available connection modes for the cable test and the
results obtained from each of them:
• Port A - Port B closed loop: Fault, Crosstalk, Distance (m.), Crossover, Polarity,
Skew (ns), Wiring.
• Port A connection with remote link: Fault, Crosstalk, Distance (m.), Crossover,
Polarity, Skew (ns).
• Port A connection without link: Fault, Crosstalk, Distance (m.).
Table 3.2: Crossover status (MDI / MDIX) and cable Wiring
Near end Far end Cable
MDI MDI Crossover
MDI MDIX Straight
MDIX MDI Straight
MDIX MDIX Crossover