Test-Um NT750 - Manual (Page 8)

LanScaper
TM
3.2.1 Jack ID -
3.2.2 Cable Test
3.2.3 Cable Length
The Jack ID test identifies what equipment, if any is, connected to the other end of
the jack or cable being tested. The test first looks for voltages being present on the connector pins.
If voltages are found in typical phone locations, tests for current levels and dial tone are run. From
these tests, the LanScaper™ will report voltage or phone type found.
If no voltages are present, testing for Ethernet link pulses commences. If link pulses are found, the
advertised capability, the pairs with link pulses and the polarity of link pulses are displayed. The
pairs with link pulses are indicated by reference to the device that would normally present pulses on
those pairs the HUB, switch or NIC assuming straight through cabling. With a cross-over cable
present, a NIC would be labeled as a HUB, etc. The AUTO indication is displayed if the device
connected is capable of auto-MDI / MDI-X. If no pulses are found, but the pattern of termination
of the cable is that of an inactive Ethernet device, it will be displayed as such.
Not finding any of the above, the LanScaper™ invokes the cable test described in the next section,
displaying single-ended cable test, full cable test or “No I/O or Cable” results.
- If a remote is sensed, the tester performs a full cable test. Upon completion of
the test, the wire map display, ID and any faults are displayed. The top line of numbers on the
display represents the connector pins on the main unit. The second line of pin numbers is the
connector pin numbers of the remote, normally being the same as the top line for a normal data
cable. If there is a miswire, the numbers on the second line will indicate the pin numbers detected.
If no connection was detected for some of the pins, the second line will be blank in those pin
locations. If a short is detected, the second line will have a flashing 'x' in that position and the
specific short condition displayed on the third line. If a split pair is detected, those pin positions on
the second line will be flashing the pin numbers detected from the remote and the specific split
condition displayed on the third line. If there are multiple errors to display on the third line, the
messages are displayed in sequence until all are displayed. The ID icon will have a number directly
below it indicating the remote ID number. If no faults are found on the cable, the length of the cable
is displayed.
If there is no remote, the LanScaper™ uses the length and cable test capability to measure a cable
for shorts, opens and split pairs (single-ended test). TEST and the pin number icons for the pairs
being tested will be on to indicate a test in progress. The results are displayed as messages on the
LCD. Because a test can take up to about 5 seconds to complete, the SEL button, which
immediately starts a new test, should be pressed whenever a new cable is connected. Partial and
erroneous results will be displayed until a complete test cycle has been run on a cable.
- The length mode measures the length of a cable by measuring its capacitance
and using the capacitance per unit length (length constant) to calculate the length. The length is
displayed on the LCD along with the current value of the length constant. The SEL button changes
the pair being measured in a 1-2, 3-6, 4-5, 7-8 and auto-select sequence. The pair number is
displayed next to the length except in auto-select mode. If a selected pair has a fault, the fault
replaces the length reading on the LCD. In auto-select mode, the tester automatically selects a pair
without a fault. The length constant is changed with the up/down arrows. The CAL icon is on
while adjusting the constant. If network termination patterns are found in the length mode, the
tester will display "T Ring Network??", "xbase-T Network?" or “Network?” (all four lines
terminated). If a remote is sensed, the ID Number is displayed.