User`s guide
21
6.0 INTERPRETING CABLE TEST RESULTS
The PASS icon will be on if the cable has all pins properly connected per
T568A/B. Neither icon will be on if the cable is cross-over (uplink) cable.
The FAIL icon will be on if there is any other condition. See Figure 6.1,
Examples of Wiring Errors.
Denition of Errors - The three classes of faults discussed below are in
order of severity. The severity has to do with the ability of a more severe
error to mask lower severity errors. For example, if there is a short in
the cable, miswires and splits pairs may not be detected for the pairs
involved in the short fault.
Short - The pair has a low resistance connection from one wire of the
pair to the other wire of the pair, to any other wire in the cable or the
shield. A short while testing with a remote is indicated by the FAIL icon
being on and ashing x’s in the appropriate pin position of the second
line of pin numbers plus one or more error message lines listing all
the pins shorted together. In the single-ended test mode, the error
messages only are displayed.
Miswire - A wire or both wires of a pair are not connected to the correct
pins at the other end of the cable. While testing with a remote, the wire
map shows the pin numbers from line 1 (main) to line 2 (remote). A
reverse pair is a special case of a miswire in which the pair is wired to
the correct pair of pins or to another designated pair of pins, but the two
leads are reversed. In single-ended test mode, these types of errors are
not detectable.
Split Pair - A split pair is an error in the twisting of the wires together
within the cable. The cables generally are made up of eight wires
twisted together in 4 pairs. These 4 pairs are designated as pairs by
the wiring standards and are intended to carry a signal and its return.
1&2, 3&6, 4&5 and 7&8 are the pairs designated by T568A/B for a RJ45
jack or plug. A cable can be wired with correct continuity but not with
correct pairing. This most often happens when the cable is terminated
consistently at both ends, but in the wrong order. A dynamic or AC
test is required to detect this type of error. If the only error is a split pair
error, the cable has correct continuity. If cross talk is not a concern, as
in at satin cable, the cable is good. While testing with a remote, the
pin numbers on the second line of the wire map with split pairs ash
and an error message is displayed listing the pin numbers of the pairs
involved in the error. In the single-ended test mode, the error message is
displayed.